diff --git a/src/modules/services-systemd/services-systemd.conf b/src/modules/services-systemd/services-systemd.conf
index 1d89ca74c..05583967f 100644
--- a/src/modules/services-systemd/services-systemd.conf
+++ b/src/modules/services-systemd/services-systemd.conf
@@ -15,12 +15,12 @@
 # *services*, *targets*, *timers*, *disable*, *disable-targets* and *mask*.
 # The value of each key is a list of entries. Each entry has two keys:
 #   - *name* is the (string) name of the service or target that is being
-#     changed. Use quotes. Don't include ".target" or ".service"
-#     in the name.
+#     changed. Use quotes. Don't include unit suffix in the name. For
+#     example, it should be "NetworkManager", not "NetworkManager.service"
 #   - *mandatory* is a boolean option, which states whether the change
 #     must be done successfully. If systemd reports an error while changing
 #     a mandatory entry, the installation will fail. When mandatory is false,
-#     errors for that entry (service or target) are ignored. If mandatory
+#     errors for that systemd unit are ignored. If mandatory
 #     is not specified, the default is false.
 #
 # An entry may also be given as a single string, which is then
@@ -46,6 +46,11 @@
 #   - name: "graphical"
 #     mandatory: true
 #
+# # Enables <name>.timer
+# timers:
+#   - name: "fstrim"
+#     mandatory: false
+#
 # # Disables <name>.service
 # disable:
 #   - name: "pacman-init"