It would make logistics and workflow a lot easier for services like ours that is time dependent, based on the last time that a client came in for a particular service. For example, if a client came in for a new set on the 1st of the month, but then he/she tried to book a two-week service at the 18-22 days after, the system would not allow them, as it has actually been closer to three weeks after their last session. Another rule-based booking criteria would be if there were a client that is new to the salon, but they try to book a fill appointment. If there were a rule that new clients could only book a new, full service or have a removal and a new service, that would save a lot of administrative headache of getting in touch with the client and notifying them that what they booked does not work for the salon. Happy to elaborate further if need be. I think a lot of salons could benefit from this and it doesn't seem very difficult to do (set a simple counter of days after last appointment and create a if/then logic rule)