What about a flat daily rate for 8.5 hour day and then an additional fee for those needing more? That way they are sure to stay within their hours?

For myself I charge $30 per day for everyone no matter what. Most of my families have had an 8-430 shift meaning drop off at 730 pickup at 450.

I get what you are saying. I have had my share of "I am paying you therefore my child will be there no matter what!" Attitudes. Luckily I have a great bunch right now and I can't complain too much.