I prefer to schedule at least a week in advance, as we currently have a number of students asking for the same time frames.  Out of respect for others trying to get on the schedule:

Please notify me at least 24 hours before class when canceling or rescheduling. Late cancellations or no-shows will be charged for the full session.

Students arriving more than 15 minutes after their appointment start time will be considered a no-show, and I will leave the office after 15 minutes. If they have contacted me that they are coming later than 15 minutes, I will be happy to wait for them and teach the rest of the time frame they originally reserved.