Hi Momma-
I think you should. Here is my reasoning on this one. My nephew goes to daycare. The agreement is that on holidays and when he is sick, he is his parents responsibility. If the grandparents (or the Auntie) want to watch him and his parents don't mind, that is fine, but that doesn't mean that the agreement for a month's worth of daycare nor the price changes. They still pay. If the parents don't think they should have to pay, then you need to set up a fee schedule- regardless of how often the children show up- if you are on call to watch them for certain hours on certain days, and they cancel, for whatever reason- they are still obligated to pay you for being available. If you do not have an agreement, then this is a discussion about what your fees as a childcare provider are. If you depend on this money, then they cannot expect to not pay. But if you agree to them not paying, that is totally your decision. I highly suggest you getting a signed contract, even if it is between friends, because business is business and you are getting paid to provide a service. This contract allows you to not have to argue or fret over what is and isn't chargeable, and also makes it clear to the parents of the children you watch that they owe so much per month regardless (unless the baby has been home sick for the majority of the month or something like that). Look up some sample contracts on line, and ask other childcare providers what their rules and requirements are. Don't feel bad about getting paid, though. Think of it as paid time off. If it still makes you uncomfortable, then get a contract with fees and regulate it like any other billing system. It takes all the questions out of the equation and makes things pretty darn clear for all parties involved.
Hope this helps!
Good luck momma
-E. M