I think the others have said it - make them pay in advance. If they don't come with the money at the first of the month, send 'em back out to get it. That way you have your money whether they want to take the lesson or not. Also, if they have already paid it tends to sharpen their ability to tell time, remember things, etc.

This puts the monkey on your back for times when you are the one to have to cancel, but you can always credit the account if it is impossible to reschedule.

I like Mooh's statement. They are scheduling your TIME, not just your expertise.

The old farmer's adage fits here: "Mule kicks me once, shame on the mule. Mule kicks me twice, shame on me."

Freightdawg