I was just wondering what everyone does for contract hours?

I have been having a problem with parents picking up whenever they feel like and not even telling me if they are going to be late or early. I tell parents to let me know when they are picking up in the afternoon as I like to have the kids ready and out the door. But my issue is I have an assistant that is going to be starting in 2 weeks. I have no idea how to give her hours when parents come and go as they please. If I schedule her until 4:30 and the parents do a late pick up until 5:30 or 6 I may need her longer but if parents pick up early then I won't need her for the later scheduled time. Another thing is when they tell you they need you at 6:30 so I am up and ready and I get a text at 7:30 they are running late because we slept in. I feel that is rude!

If I am open from 6 to 6 is it fair to charge families a fee if they come outside of their contract hours? If so what fee?

I attempted this once and a mom told me I was all about money for doing this and another told it was ridiculous that if she wanted to come early or later I shouldn't charge her. So I am not sure if this is fair or not because I see both side.

Ps I have a family who could talk and talk and talk how do you politely excuse yourself from a conversation. I have one specially who is the last to pick and she talks for a half and hour and uses my washroom every time (well almost!)! lol