Buffer time
From SimplyBook.me
Go to Manage // Services // Pen icon and:
1. Change Service duration to actual duration + buffer time (Example: actual duration 45 min, buffer time 15 min, you set up duration to 1 hour).
2. Press Hide duration link (should become bold and red).
3. Put actual duration to Service name, so the name of the service could be for example “Counseling - 45 minutes”.