Yah something like that.
I would calculate the lifetime value of a customer (how many times per month ( Year?) x fee per session X 2 year (or 3 if that is common in that industry?) Then, offer a free extra session per referral (that gets booked and paid) to preferred clients. That way, you immerse them more in your service/experience with more sessions, enable them to help you out painlessly (they have you top of mind when people ask where they should go) and gain more clients based upon good service. Maybe give them priority booking to get in quicker if they need an emergency treatment?
It is amazing how people will help out someone just starting out and it is good to build that into your business model.