Partition Manager runs every hour, 24 times a day. PM likes to sleep a lot, it wakes up every hour to do its job and goes back to sleep again (snooze mode).
It depends on what changes were made, if configuration changes were done, then a restart is a good idea so it can reload them. Each time Partition Manager starts, it needs to reload PM_CONFIG. If a restart is not done, the maximum waiting time is one hour.