That's a very broad question which no one is going to be able to answer really. It's one of those "how long is a piece of string" questions.
How many is a good amount will depend on how many hours you intend to work and when you intend to work them (eg you will be likely to get more clients if you do evenings than if you do school hours), how many treatments you are going to offer, how much advertising you are going to do, etc.
The other thing to consider is not how many clients you have but how profitable they are. You could have dozens of regular clients and be working your butt off but if you dont examine your prices and profit margins you could be working for as little money as if you only had the odd client here and there.
sorry if I've gone off track a bit but I hope that's useful for you:hug: