diff --git a/shell-completion/zsh/_bootctl b/shell-completion/zsh/_bootctl
index f107005814..0ffef94e4a 100644
--- a/shell-completion/zsh/_bootctl
+++ b/shell-completion/zsh/_bootctl
@@ -1,7 +1,7 @@
 #compdef bootctl
 # SPDX-License-Identifier: LGPL-2.1+
 
-(( $+functions[_bootctl_command] )) || _bootctl_command()
+(( $+functions[_bootctl_commands] )) || _bootctl_commands()
 {
     local -a _bootctl_cmds
     _bootctl_cmds=(
@@ -28,4 +28,4 @@ _arguments \
     '--version[Prints a short version string and exits.]' \
     '--path=[Path to the EFI System Partition (ESP)]:path:_directories' \
     '--no-variables[Do not touch EFI variables]' \
-    '*::bootctl command:_bootctl_command'
+    '*::bootctl command:_bootctl_commands'
diff --git a/shell-completion/zsh/_busctl b/shell-completion/zsh/_busctl
index 801ed48010..d66ff3e0ce 100644
--- a/shell-completion/zsh/_busctl
+++ b/shell-completion/zsh/_busctl
@@ -18,7 +18,7 @@
 # You should have received a copy of the GNU Lesser General Public License
 # along with systemd; If not, see <http://www.gnu.org/licenses/>.
 
-(( $+functions[_busctl_command] )) || _busctl_command()
+(( $+functions[_busctl_commands] )) || _busctl_commands()
 {
     local -a _busctl_cmds
     _busctl_cmds=(
@@ -68,4 +68,4 @@ _arguments \
     '--allow-interactive-authorization=[Allow interactive authorization for operation]:boolean:(1 0)' \
     '--timeout=[Maximum time to wait for method call completion]:timeout (seconds)' \
     '--augment-creds=[Extend credential data with data read from /proc/$PID]:boolean:(1 0)' \
-    '*::busctl command:_busctl_command'
+    '*::busctl command:_busctl_commands'
diff --git a/shell-completion/zsh/_coredumpctl b/shell-completion/zsh/_coredumpctl
index 720d02a3ef..e446ad349c 100644
--- a/shell-completion/zsh/_coredumpctl
+++ b/shell-completion/zsh/_coredumpctl
@@ -1,7 +1,8 @@
 #compdef coredumpctl
 # SPDX-License-Identifier: LGPL-2.1+
 
-_coredumpctl_command(){
+(( $+functions[_coredumpctl_commands] )) ||
+_coredumpctl_commands(){
     local -a _coredumpctl_cmds
     _coredumpctl_cmds=(
             'list:List available coredumps'
@@ -42,4 +43,4 @@ _arguments \
     '--debugger=[Use the given debugger]:debugger: _command_names -e' \
     {-D,--directory=}'[Use the journal files in the specified dir]:directory: _directories' \
     {-q,--quiet}'[Do not show info messages and privilege warning]' \
-    '*::coredumpctl commands:_coredumpctl_command'
+    '*::coredumpctl commands:_coredumpctl_commands'
diff --git a/shell-completion/zsh/_hostnamectl b/shell-completion/zsh/_hostnamectl
index ea86863e5a..a5c89306d1 100644
--- a/shell-completion/zsh/_hostnamectl
+++ b/shell-completion/zsh/_hostnamectl
@@ -1,6 +1,7 @@
 #compdef hostnamectl
 # SPDX-License-Identifier: LGPL-2.1+
 
+(( $+functions[_hostnamectl_set-hostname] )) ||
 _hostnamectl_set-hostname() {
     if (( CURRENT <= 3 )); then
         _message "new hostname"
@@ -9,6 +10,7 @@ _hostnamectl_set-hostname() {
     fi
 }
 
+(( $+functions[_hostnamectl_set-icon-name] )) ||
 _hostnamectl_set-icon-name() {
     if (( CURRENT <= 3 )); then
         _message "new icon name"
@@ -17,6 +19,7 @@ _hostnamectl_set-icon-name() {
     fi
 }
 
+(( $+functions[_hostnamectl_set-chassis] )) ||
 _hostnamectl_set-chassis() {
     if (( CURRENT <= 3 )); then
         _chassis=( desktop laptop convertible server tablet handset watch embedded vm container )
@@ -26,6 +29,7 @@ _hostnamectl_set-chassis() {
     fi
 }
 
+(( $+functions[_hostnamectl_set-deployment] )) ||
 _hostnamectl_set-deployment() {
     if (( CURRENT <= 3 )); then
         _message "new environment"
@@ -34,6 +38,7 @@ _hostnamectl_set-deployment() {
     fi
 }
 
+(( $+functions[_hostnamectl_set-location] )) ||
 _hostnamectl_set-location() {
     if (( CURRENT <= 3 )); then
         _message "new location"
@@ -42,7 +47,8 @@ _hostnamectl_set-location() {
     fi
 }
 
-_hostnamectl_command() {
+(( $+functions[_hostnamectl_commands] )) ||
+_hostnamectl_commands() {
     local -a _hostnamectl_cmds
     _hostnamectl_cmds=(
         "status:Show current hostname settings"
@@ -78,4 +84,4 @@ _arguments -s \
     '--no-ask-password[Do not prompt for password]' \
     {-H+,--host=}'[Operate on remote host]:userathost:_sd_hosts_or_user_at_host' \
     {-M+,--machine=}'[Operate on local container]:machines:_sd_machines' \
-    '*::hostnamectl commands:_hostnamectl_command'
+    '*::hostnamectl commands:_hostnamectl_commands'
diff --git a/shell-completion/zsh/_journalctl b/shell-completion/zsh/_journalctl
index 4bffabba96..aa6ace0485 100644
--- a/shell-completion/zsh/_journalctl
+++ b/shell-completion/zsh/_journalctl
@@ -1,7 +1,8 @@
 #compdef journalctl
 # SPDX-License-Identifier: LGPL-2.1+
 
-_list_fields() {
+(( $+functions[_journalctl_fields] )) ||
+_journalctl_fields() {
     local -a journal_fields
     journal_fields=(MESSAGE{,_ID} PRIORITY CODE_{FILE,LINE,FUNC}
                     ERRNO SYSLOG_{FACILITY,IDENTIFIER,PID}
@@ -16,12 +17,13 @@ _list_fields() {
                     __CURSOR __{REALTIME,MONOTONIC}_TIMESTAMP)
     case $_jrnl_none in
         yes) _values -s '=' 'possible fields' \
-                "${journal_fields[@]}:value:_journal_fields ${words[CURRENT]%%=*}" ;;
+                "${journal_fields[@]}:value:_journalctl_field_values ${words[CURRENT]%%=*}" ;;
         *)  _describe 'possible fields' journal_fields ;;
     esac
 }
 
-_journal_none() {
+(( $+functions[_journalctl_none] )) ||
+_journalctl_none() {
     local -a _commands _files _jrnl_none
     # Setting use-cache will slow this down considerably
     _commands=( ${"$(_call_program commands "$service $_sys_service_mgr -F _EXE" 2>/dev/null)"} )
@@ -29,10 +31,11 @@ _journal_none() {
     _alternative : \
         'files:/dev files:_files -W /dev -P /dev/' \
         "commands:commands:($_commands[@])" \
-        'fields:fields:_list_fields'
+        'fields:fields:_journalctl_fields'
 }
 
-_journal_fields() {
+(( $+functions[_journalctl_field_values] )) ||
+_journalctl_field_values() {
     local -a _fields cmd
     cmd=("journalctl $_sys_service_mgr" "-F ${@[-1]}" "2>/dev/null" )
     _fields=$(_call_program fields $cmd[@])
@@ -43,7 +46,8 @@ _journal_fields() {
     _describe 'possible values' _fields
 }
 
-_journal_boots() {
+(( $+functions[_journalctl_boots] )) ||
+_journalctl_boots() {
   local -a _bootid _previousboots
   _bootid=( ${(f)"$(_call_program bootid "$service -F _BOOT_ID")"}  )
   _previousboots=( -{1..${#_bootid}} )
@@ -92,18 +96,18 @@ _arguments -s \
     {-x,--catalog}'[Show explanatory texts with each log line]' \
     {-q,--quiet}"[Don't show privilege warning]" \
     {-m,--merge}'[Show entries from all available journals]' \
-    {-b+,--boot=}'[Show data only from the specified boot or offset]::boot id or offset:_journal_boots' \
+    {-b+,--boot=}'[Show data only from the specified boot or offset]::boot id or offset:_journalctl_boots' \
     '--list-boots[List boots ordered by time]' \
     {-k,--dmesg}'[Show only kernel messages from the current boot]' \
-    {-u+,--unit=}'[Show data only from the specified unit]:units:_journal_fields _SYSTEMD_UNIT' \
-    '--user-unit=[Show data only from the specified user session unit]:units:_journal_fields USER_UNIT' \
-    {-p+,--priority=}'[Show only messages within the specified priority range]:priority:_journal_fields PRIORITY' \
-    {-t+,--identifier=}'[Show only messages with the specified syslog identifier]:identifier:_journal_fields SYSLOG_IDENTIFIER' \
-    {-c+,--cursor=}'[Start showing entries from the specified cursor]:cursors:_journal_fields __CURSORS' \
-    '--after-cursor=[Start showing entries from after the specified cursor]:cursors:_journal_fields __CURSORS' \
+    {-u+,--unit=}'[Show data only from the specified unit]:units:_journalctl_field_values _SYSTEMD_UNIT' \
+    '--user-unit=[Show data only from the specified user session unit]:units:_journalctl_field_values USER_UNIT' \
+    {-p+,--priority=}'[Show only messages within the specified priority range]:priority:_journalctl_field_values PRIORITY' \
+    {-t+,--identifier=}'[Show only messages with the specified syslog identifier]:identifier:_journalctl_field_values SYSLOG_IDENTIFIER' \
+    {-c+,--cursor=}'[Start showing entries from the specified cursor]:cursors:_journalctl_field_values __CURSORS' \
+    '--after-cursor=[Start showing entries from after the specified cursor]:cursors:_journalctl_field_values __CURSORS' \
     '--since=[Start showing entries on or newer than the specified date]:YYYY-MM-DD HH\:MM\:SS' \
     '--until=[Stop showing entries on or older than the specified date]:YYYY-MM-DD HH\:MM\:SS' \
-    {-F,--field=}'[List all values a certain field takes]:Fields:_list_fields' \
+    {-F,--field=}'[List all values a certain field takes]:Fields:_journalctl_fields' \
     '--system[Show system and kernel messages]' \
     '--user[Show messages from user services]' \
     '(--directory -D -M --machine --root --file)'{-M+,--machine=}'[Operate on local container]:machines:_sd_machines' \
@@ -121,4 +125,4 @@ _arguments -s \
     '--interval=[Time interval for changing the FSS sealing key]:time interval' \
     '--verify[Verify journal file consistency]' \
     '--verify-key=[Specify FSS verification key]:FSS key' \
-    '*::default: _journal_none'
+    '*::default: _journalctl_none'
diff --git a/shell-completion/zsh/_kernel-install b/shell-completion/zsh/_kernel-install
index 6358a64589..14793c2f3f 100644
--- a/shell-completion/zsh/_kernel-install
+++ b/shell-completion/zsh/_kernel-install
@@ -1,7 +1,8 @@
 #compdef kernel-install
 # SPDX-License-Identifier: LGPL-2.1+
 
-_images(){
+(( $+functions[_kernel-install_images] )) ||
+_kernel-install_images(){
     if [[ "$words[2]" == "remove" ]]; then
         _message 'No more options'
     else
@@ -9,7 +10,8 @@ _images(){
     fi
 }
 
-_kernels(){
+(( $+functions[_kernel-install_kernels] )) ||
+_kernel-install_kernels(){
     read _MACHINE_ID < /etc/machine-id
     _kernel=( /lib/modules/[0-9]* )
     if [[ "$cmd" == "remove" && -n "$_MACHINE_ID" ]]; then
@@ -21,7 +23,7 @@ _kernels(){
 
 _arguments \
     '1::add or remove:(add remove)' \
-    '2::kernel versions:_kernels' \
-    '3::kernel images:_images'
+    '2::kernel versions:_kernel-install_kernels' \
+    '3::kernel images:_kernel-install_images'
 
 #vim: set ft=zsh sw=4 ts=4 et
diff --git a/shell-completion/zsh/_localectl b/shell-completion/zsh/_localectl
index e5ec65b53b..569f4f294c 100644
--- a/shell-completion/zsh/_localectl
+++ b/shell-completion/zsh/_localectl
@@ -1,6 +1,7 @@
 #compdef localectl
 # SPDX-License-Identifier: LGPL-2.1+
 
+(( $+functions[_localectl_set-locale] )) ||
 _localectl_set-locale() {
     local -a _locales locale_fields
     locale_fields=(LANG LANGUAGE LC_CTYPE LC_NUMERIC LC_TIME \
@@ -21,6 +22,7 @@ _localectl_set-locale() {
     fi
 }
 
+(( $+functions[_localectl_set-keymap] )) ||
 _localectl_set-keymap() {
     local -a _keymaps
     if (( CURRENT <= 3 )); then
@@ -31,6 +33,7 @@ _localectl_set-keymap() {
     fi
 }
 
+(( $+functions[_localectl_set-x11-keymap] )) ||
 _localectl_set-x11-keymap() {
     if (( $+commands[pkg-config] )); then
         local -a _file _layout _model _variant _options
@@ -56,7 +59,8 @@ _localectl_set-x11-keymap() {
     fi
 }
 
-_localectl_command() {
+(( $+functions[_localectl_commands] )) ||
+_localectl_commands() {
     local -a _localectl_cmds
     _localectl_cmds=(
         'status:Show current locale settings'
@@ -91,4 +95,4 @@ _arguments \
     '--no-ask-password[Do not prompt for password]' \
     {-H+,--host=}'[Operate on remote host]:userathost:_sd_hosts_or_user_at_host' \
     {-M+,--machine=}'[Operate on local container]:machine' \
-    '*::localectl commands:_localectl_command'
+    '*::localectl commands:_localectl_commands'
diff --git a/shell-completion/zsh/_loginctl b/shell-completion/zsh/_loginctl
index 03dde9a891..44d6d08c98 100644
--- a/shell-completion/zsh/_loginctl
+++ b/shell-completion/zsh/_loginctl
@@ -1,6 +1,7 @@
 #compdef loginctl
 # SPDX-License-Identifier: LGPL-2.1+
 
+(( $+functions[_loginctl_all_sessions] )) ||
 _loginctl_all_sessions() {
   local session description
   loginctl --no-legend list-sessions | while read -r session description; do
@@ -9,6 +10,7 @@ _loginctl_all_sessions() {
   done
 }
 
+(( $+functions[_loginctl_all_users] )) ||
 _loginctl_all_users() {
   local uid description
   loginctl --no-legend list-users | while read -r uid description; do
@@ -17,6 +19,7 @@ _loginctl_all_users() {
   done
 }
 
+(( $+functions[_loginctl_all_seats] )) ||
 _loginctl_all_seats() {
   local seat description
   loginctl --no-legend list-seats | while read -r seat description; do
@@ -107,7 +110,7 @@ done
 # no loginctl completion for:
 # [STANDALONE]='list-sessions list-users list-seats flush-devices'
 
-(( $+functions[_loginctl_command] )) || _loginctl_command()
+(( $+functions[_loginctl_commands] )) || _loginctl_commands()
 {
   local -a _loginctl_cmds
   _loginctl_cmds=(
@@ -170,4 +173,4 @@ _arguments -s \
     '--no-ask-password[Do not ask for system passwords]' \
     {-n+,--lines=}'[Number of journal entries to show]' \
     {-o+,--output=}'[Change journal output mode]:output modes:_sd_outputmodes' \
-    '*::loginctl command:_loginctl_command'
+    '*::loginctl command:_loginctl_commands'
diff --git a/shell-completion/zsh/_machinectl b/shell-completion/zsh/_machinectl
index a00fc91021..4561e4db75 100644
--- a/shell-completion/zsh/_machinectl
+++ b/shell-completion/zsh/_machinectl
@@ -1,13 +1,15 @@
 #compdef machinectl
 # SPDX-License-Identifier: LGPL-2.1+
 
-__get_available_machines () {
+(( $+functions[__machinectl_get_machines] )) ||
+__machinectl_get_machines () {
     machinectl --no-legend list-images | {while read -r a b; do echo $a; done;}
 }
 
-_available_machines() {
+(( $+functions[_machinectl_machines] )) ||
+_machinectl_machines() {
     local -a _machines
-    _machines=("${(fo)$(__get_available_machines)}")
+    _machines=("${(fo)$(__machinectl_get_machines)}")
     typeset -U _machines
     if [[ -n "$_machines" ]]; then
         _describe 'machines' _machines
@@ -16,7 +18,7 @@ _available_machines() {
     fi
 }
 
-(( $+functions[_machinectl_command] )) || _machinectl_command()
+(( $+functions[_machinectl_commands] )) || _machinectl_commands()
 {
   local -a _machinectl_cmds
   _machinectl_cmds=(
@@ -61,9 +63,9 @@ _available_machines() {
           list*|cancel-transfer|pull-tar|pull-raw)
             msg="no options" ;;
           clone)
-            _available_machines ;;
+            _machinectl_machines ;;
           start)
-            _available_machines ;;
+            _machinectl_machines ;;
           *)
             _sd_machines
         esac
@@ -100,4 +102,4 @@ _arguments \
   {-o+,--output=}'[Change journal output mode.]:output modes:_sd_outputmodes' \
   '--verify=[Verification mode for downloaded images.]:verify:(no checksum signature)' \
   '--force[Download image even if already exists.]' \
-  '*::machinectl command:_machinectl_command'
+  '*::machinectl command:_machinectl_commands'
diff --git a/shell-completion/zsh/_networkctl b/shell-completion/zsh/_networkctl
index ea485d653c..ab62a6d9bf 100644
--- a/shell-completion/zsh/_networkctl
+++ b/shell-completion/zsh/_networkctl
@@ -1,7 +1,8 @@
 #compdef networkctl
 # SPDX-License-Identifier: LGPL-2.1+
 
-_networkctl_command(){
+(( $+functions[_networkctl_commands] )) ||
+_networkctl_commands(){
     local -a _networkctl_cmds
     _networkctl_cmds=(
             'list:List existing links'
@@ -34,4 +35,4 @@ _arguments \
     '--no-legend[Do not print the column headers]' \
     {-h,--help}'[Show this help]' \
     '--version[Show package version]' \
-    '*::networkctl commands:_networkctl_command'
+    '*::networkctl commands:_networkctl_commands'
diff --git a/shell-completion/zsh/_sd_machines b/shell-completion/zsh/_sd_machines
index ab35cf84b3..e783620b97 100644
--- a/shell-completion/zsh/_sd_machines
+++ b/shell-completion/zsh/_sd_machines
@@ -1,11 +1,13 @@
 #autoload
 # SPDX-License-Identifier: LGPL-2.1+
-__get_machines () {
+
+(( $+functions[__sd_machines_get_machines] )) ||
+__sd_machines_get_machines () {
         machinectl --full --no-legend --no-pager list |  {while read -r a b; do echo $a; done;};
 }
 
 local -a _machines
-_machines=("${(fo)$(__get_machines)}")
+_machines=("${(fo)$(__sd_machines_get_machines)}")
 typeset -U _machines
 if [[ -n "$_machines" ]]; then
         _describe 'machines' _machines
diff --git a/shell-completion/zsh/_systemctl.in b/shell-completion/zsh/_systemctl.in
index 782d243131..590fc49604 100644
--- a/shell-completion/zsh/_systemctl.in
+++ b/shell-completion/zsh/_systemctl.in
@@ -1,7 +1,7 @@
 #compdef systemctl
 # SPDX-License-Identifier: LGPL-2.1+
 
-(( $+functions[_systemctl_command] )) || _systemctl_command()
+(( $+functions[_systemctl_commands] )) || _systemctl_commands()
 {
   local -a _systemctl_cmds
   _systemctl_cmds=(
@@ -95,6 +95,7 @@
   fi
 }
 
+# @todo _systemd-run has a helper with the same name, so we must redefine
 __systemctl()
 {
   systemctl $_sys_service_mgr --full --no-legend --no-pager "$@" 2>/dev/null
@@ -102,6 +103,7 @@ __systemctl()
 
 
 # Fills the unit list
+(( $+functions[_systemctl_all_units] )) ||
 _systemctl_all_units()
 {
   if ( [[ ${+_sys_all_units} -eq 0 ]] || _cache_invalid SYS_ALL_UNITS$_sys_service_mgr ) ||
@@ -113,6 +115,7 @@ _systemctl_all_units()
 }
 
 # Fills the unit list including all file units
+(( $+functions[_systemctl_really_all_units] )) ||
 _systemctl_really_all_units()
 {
   local -a all_unit_files;
@@ -128,6 +131,7 @@ _systemctl_really_all_units()
   fi
 }
 
+(( $+functions[_filter_units_by_property] )) ||
 _filter_units_by_property() {
   local property=$1 value=$2; shift 2
   local -a units; units=("${(q-)@}")
@@ -136,16 +140,19 @@ _filter_units_by_property() {
   echo -E - "${(@g:o:)${(k@)props[(Re)$property=$value]}#Id=}"
 }
 
+(( $+functions[_systemctl_get_non_template_names] )) ||
 _systemctl_get_non_template_names() { echo -E - ${^${(R)${(f)"$(
     __systemctl $mode list-unit-files "$PREFIX*"
     __systemctl $mode list-units --all "$PREFIX*"
   )"}:#*@.*}%%[[:space:]]*} }
 
+(( $+functions[_systemctl_get_template_names] )) ||
 _systemctl_get_template_names() { echo -E - ${^${(M)${(f)"$(__systemctl list-unit-files "$PREFIX*" )"}##*@.[^[:space:]]##}%%@.*}\@ }
 
-
+(( $+functions[_systemctl_active_units] )) ||
 _systemctl_active_units()  {_sys_active_units=(  ${${(f)"$(__systemctl list-units "$PREFIX*" )"}%% *} )}
 
+(( $+functions[_systemctl_startable_units] )) ||
 _systemctl_startable_units(){
   _sys_startable_units=( $( _filter_units_by_property ActiveState inactive $(
     _filter_units_by_property CanStart yes ${${${(f)"$(
@@ -155,6 +162,7 @@ _systemctl_startable_units(){
   )) )
 }
 
+(( $+functions[_systemctl_restartable_units] )) ||
 _systemctl_restartable_units(){
   _sys_restartable_units=( $( _filter_units_by_property CanStart yes ${${${(f)"$(
     __systemctl $mode list-unit-files --state enabled,disabled,static "$PREFIX*"
@@ -162,7 +170,10 @@ _systemctl_restartable_units(){
   )"}:#*@.*}%%[[:space:]]*} ) )
 }
 
+(( $+functions[_systemctl_failed_units] )) ||
 _systemctl_failed_units()  {_sys_failed_units=( ${${(f)"$(__systemctl list-units --state=failed "$PREFIX*" )"}%% *} ) }
+
+(( $+functions[_systemctl_unit_state] )) ||
 _systemctl_unit_state() { typeset -gA _sys_unit_state; _sys_unit_state=( $(__systemctl list-unit-files "$PREFIX*" ) ) }
 
 local fun
@@ -316,6 +327,7 @@ done
 #                  emergency exit halt kexec list-jobs list-units
 #                  list-unit-files poweroff reboot rescue show-environment'
 
+(( $+functions[_systemctl_caching_policy] )) ||
 _systemctl_caching_policy()
 {
   local _sysunits
@@ -336,19 +348,22 @@ _systemctl_caching_policy()
   return 1
 }
 
-_unit_states() {
+(( $+functions[_systemctl_unit_states] )) ||
+_systemctl_unit_states() {
     local -a _states
     _states=("${(fo)$(__systemctl --state=help)}")
     _values -s , "${_states[@]}"
 }
 
-_unit_types() {
+(( $+functions[_systemctl_unit_types] )) ||
+_systemctl_unit_types() {
     local -a _types
     _types=("${(fo)$(__systemctl -t help)}")
     _values -s , "${_types[@]}"
 }
 
-_unit_properties() {
+(( $+functions[_systemctl_unit_properties] )) ||
+_systemctl_unit_properties() {
   if ( [[ ${+_sys_all_properties} -eq 0 ]] || _cache_invalid SYS_ALL_PROPERTIES$_sys_service_mgr ) ||
     ! _retrieve_cache SYS_ALL_PROPERTIES$_sys_service_mgr;
   then
@@ -358,7 +373,8 @@ _unit_properties() {
   _values -s , "${_sys_all_properties[@]}"
 }
 
-_job_modes() {
+(( $+functions[_systemctl_job_modes] )) ||
+_systemctl_job_modes() {
     local -a _modes
     _modes=(fail replace replace-irreversibly isolate ignore-dependencies ignore-requirements flush)
     _values -s , "${_modes[@]}"
@@ -371,10 +387,10 @@ local _sys_service_mgr=${${words:*_modes}[(R)(${(j.|.)_modes})]}
 _arguments -s \
     {-h,--help}'[Show help]' \
     '--version[Show package version]' \
-    {-t+,--type=}'[List only units of a particular type]:unit type:_unit_types' \
-    '--state=[Display units in the specified state]:unit state:_unit_states' \
-    '--job-mode=[Specify how to deal with other jobs]:mode:_job_modes' \
-    {-p+,--property=}'[Show only properties by specific name]:unit property:_unit_properties' \
+    {-t+,--type=}'[List only units of a particular type]:unit type:_systemctl_unit_types' \
+    '--state=[Display units in the specified state]:unit state:_systemctl_unit_states' \
+    '--job-mode=[Specify how to deal with other jobs]:mode:_systemctl_job_modes' \
+    {-p+,--property=}'[Show only properties by specific name]:unit property:_systemctl_unit_properties' \
     {-a,--all}'[Show all units/properties, including dead/empty ones]' \
     '--reverse[Show reverse dependencies]' \
     '--after[Show units ordered after]' \
@@ -404,4 +420,4 @@ _arguments -s \
     '--firmware-setup[Tell the firmware to show the setup menu on next boot]' \
     '--plain[When used with list-dependencies, print output as a list]' \
     '--failed[Show failed units]' \
-    '*::systemctl command:_systemctl_command'
+    '*::systemctl command:_systemctl_commands'
diff --git a/shell-completion/zsh/_systemd-analyze b/shell-completion/zsh/_systemd-analyze
index 56982e3d11..64d418e643 100644
--- a/shell-completion/zsh/_systemd-analyze
+++ b/shell-completion/zsh/_systemd-analyze
@@ -1,29 +1,34 @@
 #compdef systemd-analyze
 # SPDX-License-Identifier: LGPL-2.1+
 
-_systemd_analyze_log-level() {
+(( $+functions[_systemd-analyze_log-level] )) ||
+_systemd-analyze_log-level() {
     local -a _levels
     _levels=(debug info notice warning err crit alert emerg)
     _describe -t level 'logging level' _levels || compadd "$@"
 }
 
-_systemd_analyze_log-target() {
+(( $+functions[_systemd-analyze_log-target] )) ||
+_systemd-analyze_log-target() {
     local -a _targets
     _targets=(console journal kmsg journal-or-kmsg null)
     _describe -t target 'logging target' _targets || compadd "$@"
 }
 
-_systemd_analyze_verify() {
+(( $+functions[_systemd-analyze_verify] )) ||
+_systemd-analyze_verify() {
     _sd_unit_files
 }
 
-_systemd_analyze_service-watchdogs() {
+(( $+functions[_systemd-analyze_service-watchdogs] )) ||
+_systemd-analyze_service-watchdogs() {
     local -a _states
     _states=(on off)
     _describe -t state 'state' _states || compadd "$@"
 }
 
-_systemd_analyze_command(){
+(( $+functions[_systemd-analyze_commands] )) ||
+_systemd-analyze_commands(){
     local -a _systemd_analyze_cmds
     # Descriptions taken from systemd-analyze --help.
     _systemd_analyze_cmds=(
@@ -48,8 +53,8 @@ _systemd_analyze_command(){
         local curcontext="$curcontext"
         cmd="${${_systemd_analyze_cmds[(r)$words[1]:*]%%:*}}"
         if (( $#cmd )); then
-            if (( $+functions[_systemd_analyze_$cmd] )) && (( CURRENT == 2 )); then
-                _systemd_analyze_$cmd
+            if (( $+functions[_systemd-analyze_$cmd] )) && (( CURRENT == 2 )); then
+                _systemd-analyze_$cmd
             else
                 _message "no more options"
             fi
@@ -74,4 +79,4 @@ _arguments \
     '--to-pattern=[When generating a dependency graph, filter only destinations]:GLOB' \
     {-H+,--host=}'[Operate on remote host]:userathost:_sd_hosts_or_user_at_host' \
     {-M+,--machine=}'[Operate on local container]:machine:_sd_machines' \
-    '*::systemd-analyze commands:_systemd_analyze_command'
+    '*::systemd-analyze commands:_systemd-analyze_commands'
diff --git a/shell-completion/zsh/_systemd-delta b/shell-completion/zsh/_systemd-delta
index 44e4cb3791..e07bbc8b2b 100644
--- a/shell-completion/zsh/_systemd-delta
+++ b/shell-completion/zsh/_systemd-delta
@@ -1,7 +1,8 @@
 #compdef systemd-delta
 # SPDX-License-Identifier: LGPL-2.1+
 
-_delta_type() {
+(( $+functions[_systemd-delta_types] )) ||
+_systemd-delta_types() {
     local -a _delta_types
     _delta_types=(masked equivalent redirected overridden unchanged)
     _values -s , "${_delta_types[@]}"
@@ -12,5 +13,5 @@ _arguments \
     '--version[Show package version]' \
     '--no-pager[Do not pipe output into a pager]' \
     '--diff=[Show a diff when overridden files differ]:boolean:(1 0)' \
-    {-t+,--type=}'[Only display a selected set of override types]:types:_delta_type' \
+    {-t+,--type=}'[Only display a selected set of override types]:types:_systemd-delta_types' \
     ':SUFFIX:(tmpfiles.d sysctl.d systemd/system)'
diff --git a/shell-completion/zsh/_systemd-inhibit b/shell-completion/zsh/_systemd-inhibit
index 764713e28a..7c40e49ae4 100644
--- a/shell-completion/zsh/_systemd-inhibit
+++ b/shell-completion/zsh/_systemd-inhibit
@@ -1,7 +1,8 @@
 #compdef systemd-inhibit
 # SPDX-License-Identifier: LGPL-2.1+
 
-_systemd_inhibit_command(){
+(( $+functions[_systemd-inhibit_commands] )) ||
+_systemd-inhibit_commands(){
     if (( CURRENT == 1 )); then
         compset -q
         _normal
@@ -17,7 +18,8 @@ _systemd_inhibit_command(){
     fi
 }
 
-_inhibit_what() {
+(( $+functions[_systemd-inhibit_what] )) ||
+_systemd-inhibit_what() {
     local _inhibit
     _inhibit=(shutdown sleep idle handle-power-key handle-suspend-key handle-hibernate-key handle-lid-switch)
     _values -s : "${_inhibit[@]}"
@@ -31,4 +33,4 @@ _arguments \
     '--why=[A descriptive string why is being inhibited]:reason for the lock:' \
     '--mode=[One of block or delay]:lock mode:( block delay )' \
     '--list[List active inhibitors]' \
-    '*:commands:_systemd_inhibit_command'
+    '*:commands:_systemd-inhibit_commands'
diff --git a/shell-completion/zsh/_systemd-nspawn b/shell-completion/zsh/_systemd-nspawn
index e0bedee2aa..abaabfc895 100644
--- a/shell-completion/zsh/_systemd-nspawn
+++ b/shell-completion/zsh/_systemd-nspawn
@@ -1,7 +1,8 @@
 #compdef systemd-nspawn
 # SPDX-License-Identifier: LGPL-2.1+
 
-_nspawn-caps(){
+(( $+functions[_systemd-nspawn_caps] )) ||
+_systemd-nspawn_caps(){
     local -a _caps
     _caps=( CAP_CHOWN CAP_DAC_OVERRIDE CAP_DAC_READ_SEARCH
             CAP_FOWNER CAP_FSETID CAP_IPC_OWNER CAP_KILL CAP_LEASE CAP_LINUX_IMMUTABLE
@@ -33,8 +34,8 @@ _arguments \
     {--port=,-p+}'[Expose a container IP port on the host.]: : _message port' \
     {--selinux-context=,-Z+}'[Sets the SELinux security context to be used to label processes in the container.]: : _message "SELinux context"' \
     {--selinux-apifs-context=,-L+}'[Sets the SELinux security context to be used to label files in the virtual API file systems in the container.]: : _message "SELinux context"' \
-    '--capability=[List one or more additional capabilities to grant the container.]:capabilities:_nspawn-caps' \
-    '--drop-capability=[Specify one or more additional capabilities to drop for the containerm]:capabilities:_nspawn-caps' \
+    '--capability=[List one or more additional capabilities to grant the container.]:capabilities:_systemd-nspawn_caps' \
+    '--drop-capability=[Specify one or more additional capabilities to drop for the containerm]:capabilities:_systemd-nspawn_caps' \
     "--link-journal=[Control whether the container's journal shall be made visible to the host system.]:options:(no host guest auto)" \
     '-j[Equivalent to --link-journal=guest.]' \
     '--read-only[Mount the root file system read only for the container.]' \
diff --git a/shell-completion/zsh/_systemd-resolve b/shell-completion/zsh/_systemd-resolve
index b54d22f816..c4664422ec 100644
--- a/shell-completion/zsh/_systemd-resolve
+++ b/shell-completion/zsh/_systemd-resolve
@@ -17,24 +17,28 @@
 # You should have received a copy of the GNU Lesser General Public License
 # along with systemd; If not, see <http://www.gnu.org/licenses/>.
 
-_dns_protocol() {
+(( $+functions[_systemd-resolve_protocols] )) ||
+_systemd-resolve_protocols() {
     local -a _protocol
     _protocol=( $(_call_program protocol ${service} --legend=no --protocol help; echo help) )
     _values 'protocol' "$_protocol[@]"
 }
 
-_dns_type() {
+(( $+functions[_systemd-resolve_types] )) ||
+_systemd-resolve_types() {
     local -a _type
     _type=( $(_call_program type ${service} --legend=no --type help; echo help) )
     _values 'type' "$_type[@]"
 }
 
-_dns_class() {
+(( $+functions[_systemd-resolve_classes] )) ||
+_systemd-resolve_classes() {
     local -a _class
     _class=( $(_call_program class ${service} --legend=no --class help; echo help) )
     _values 'class' "$_class[@]"
 }
 
+(( $+functions[_systemd-resolve_none] )) ||
 _systemd-resolve_none() {
     _alternative : \
         'domain:DNS address:' \
@@ -48,9 +52,9 @@ _arguments \
     '-4[Resolve IPv4 addresses]' \
     '-6[Resolve IPv6 addresses]' \
     {-i+,--interface=}'[Look on interface]:interface:_net_interfaces' \
-    {-p+,--protocol=}'[Look via protocol]:protocol:_dns_protocol' \
-    {-t+,--type=}'[Query RR with DNS type]:type:_dns_type' \
-    {-c+,--class=}'[Query RR with DNS class]:class:_dns_class' \
+    {-p+,--protocol=}'[Look via protocol]:protocol:_systemd-resolve_protocols' \
+    {-t+,--type=}'[Query RR with DNS type]:type:_systemd-resolve_types' \
+    {-c+,--class=}'[Query RR with DNS class]:class:_systemd-resolve_classes' \
     '--service[Resolve services]' \
     '--service-address=no[Do not resolve address for services]' \
     '--service-txt=no[Do not resolve TXT records for services]' \
diff --git a/shell-completion/zsh/_systemd-run b/shell-completion/zsh/_systemd-run
index a8a8e6fe34..81017180a7 100644
--- a/shell-completion/zsh/_systemd-run
+++ b/shell-completion/zsh/_systemd-run
@@ -1,20 +1,23 @@
 #compdef systemd-run
 # SPDX-License-Identifier: LGPL-2.1+
 
+# @todo _systemctl has a helper with the same name, so we must redefine
 __systemctl() {
         local -a _modes
         _modes=("--user" "--system")
         systemctl ${words:*_modes} --full --no-legend --no-pager "$@" 2>/dev/null
 }
 
-__get_slices () {
+(( $+functions[__systemd-run_get_slices] )) ||
+__systemd-run_get_slices () {
         __systemctl list-units --all -t slice \
         | { while read -r a b; do echo $a; done; };
 }
 
-__slices () {
+(( $+functions[__systemd-run_slices] )) ||
+__systemd-run_slices () {
         local -a _slices
-        _slices=(${(fo)"$(__get_slices)"})
+        _slices=(${(fo)"$(__systemd-run_get_slices)"})
         typeset -U _slices
         _describe 'slices' _slices
 }
@@ -43,7 +46,7 @@ _arguments \
                 ProtectSystem= ProtectHome= RuntimeDirectory= PassEnvironment= \
                 ))' \
         '--description=[Description for unit]:description' \
-        '--slice=[Run in the specified slice]:slices:__slices' \
+        '--slice=[Run in the specified slice]:slices:__systemd-run_slices' \
         {-r,--remain-after-exit}'[Leave service around until explicitly stopped]' \
         '--send-sighup[Send SIGHUP when terminating]' \
         '--service-type=[Service type]:type:(simple forking oneshot dbus notify idle)' \
diff --git a/shell-completion/zsh/_udevadm b/shell-completion/zsh/_udevadm
index c6bd685aee..020759b006 100644
--- a/shell-completion/zsh/_udevadm
+++ b/shell-completion/zsh/_udevadm
@@ -1,6 +1,7 @@
 #compdef udevadm
 # SPDX-License-Identifier: LGPL-2.1+
 
+(( $+functions[_udevadm_info] )) ||
 _udevadm_info(){
     _arguments \
         '--query=[Query the database for specified type of device data. It needs the --path or --name to identify the specified device.]:type:(name symlink path property all)' \
@@ -15,6 +16,7 @@ _udevadm_info(){
         '--cleanup-db[Cleanup the udev database.]'
 }
 
+(( $+functions[_udevadm_trigger] )) ||
 _udevadm_trigger(){
     _arguments \
         '--verbose[Print the list of devices which will be triggered.]' \
@@ -31,6 +33,7 @@ _udevadm_trigger(){
         '--parent-match=[Trigger events for all children of a given device.]'
 }
 
+(( $+functions[_udevadm_settle] )) ||
 _udevadm_settle(){
     _arguments \
        '--timeout=[Maximum number of seconds to wait for the event queue to become empty.]' \
@@ -41,6 +44,7 @@ _udevadm_settle(){
        '--help[Print help text.]'
 }
 
+(( $+functions[_udevadm_control] )) ||
 _udevadm_control(){
     _arguments \
         '--exit[Signal and wait for systemd-udevd to exit.]' \
@@ -54,6 +58,7 @@ _udevadm_control(){
         '--help[Print help text.]'
 }
 
+(( $+functions[_udevadm_monitor] )) ||
 _udevadm_monitor(){
     _arguments \
         '--kernel[Print the kernel uevents.]' \
@@ -64,6 +69,7 @@ _udevadm_monitor(){
         '--help[Print help text.]'
 }
 
+(( $+functions[_udevadm_test] )) ||
 _udevadm_test(){
     _arguments \
         '--action=[The action string.]:actions:(add change remove)' \
@@ -72,6 +78,7 @@ _udevadm_test(){
         '*::devpath:_files -P /sys/ -W /sys'
 }
 
+(( $+functions[_udevadm_test-builtin] )) ||
 _udevadm_test-builtin(){
     if (( CURRENT == 2 )); then
     _arguments \
@@ -87,6 +94,7 @@ _udevadm_test-builtin(){
     fi
 }
 
+(( $+functions[_udevadm_mounts] )) ||
 _udevadm_mounts(){
   local dev_tmp dpath_tmp mp_tmp mline
 
@@ -104,8 +112,8 @@ _udevadm_mounts(){
     'directories:mount point:compadd -a mp_tmp'
 }
 
-
-_udevadm_command(){
+(( $+functions[_udevadm_commands] )) ||
+_udevadm_commands(){
     local -a _udevadm_cmds
     _udevadm_cmds=(
         'info:query sysfs or the udev database'
@@ -139,4 +147,4 @@ _arguments \
     '--debug[Print debug messages to stderr]' \
     '--version[Print version number]' \
     '--help[Print help text]' \
-    '*::udevadm commands:_udevadm_command'
+    '*::udevadm commands:_udevadm_commands'