Buffer time
From SimplyBook.me
Go to Manage // Services and switch to "Time details" tab(new interface) or Manage // Services // Pen icon(old interface) 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. Enable "Hide duration on the booking page" option(new interface) or press "Hide duration" link (should become bold and red)(old interface) .
3. Put actual duration to Service name, so the name of the service could be for example “Counseling - 45 minutes”.
new interface:
old interface: