The office where my T works says they require 24 hour notice or there is a charge for missed appointments. I don't remember signing a formal agreement about it, though.

There are several T's in that office so I think the rule is there as a blanket statement.

When I have had to cancel, the I expressed concern about the 24 hour notice rule. T said she doesn't want me worrying about that. We talk on the phone for an hour, instead, if possible, if ice or something keeps me from our appointment. She's pretty understanding.