You could say to them, I want to establish payment prior to care so I can have money to pay for food, supplies, crafts. You can say you want to have all parents do this, to make it fair and to ensure that you are paid on time. Let them know that you appreciate that they pay prompty but that this is for any future clients and you just want the same method for everyone.

With that said, decide if it's really worth it to you to raise this issue with them. If they are really opposed to it, is it worth losing good parents?

For me, all my families pay upfront on the Monday except for one family that pays in cash at the end of the week. They are usually very good about it but there has been a few times, when they have forgotten and brought me the money on Saturday. Lets just say from now on, for any future clients I only accept post dated cheques, or payment at the beginning of the week. But because I've had this Friday payday arrangement with them now for 1 year, I'm not going to bother changing it.