Pay is normally by the day, half-week, or week... Some people come and only take one class a day, some take every class (8-9 a day), most are somewhere in between. Totally up to you, what physical shape you're in, what teachers you want to see, how you feel like spending your time, other things you want to do, etc.
Personally I usually like taking all the classes, and I know I'm not the only one
. But you'll see how you feel.