Salonist provides Facility to differentiate customers in two ways i.e. Active and Inactive customers.
ACTIVE CUSTOMERS: The customers who visit your salon on regular basis for example twice a month or at least once each month, Also you can select active period by your own choice it can be 20 days or 30 days as shown below.
INACTIVE CUSTOMERS: The customers who do not visit your salon on regular basis so once they cross active period time slot, then they will be automatically shifted into the category of inactive clients.
To set time period for active/inactive check the way here
1. Go to Setup >> Business Details
Under Client Active/Inactive Time Period you can set the duration. it can be for a month, 30 days or more than 30 days. it is up to you.
Also, here is the video tutorial for your reference