I would think it would be fair to not charge them if you are off the same time.

I take unpaid time off and the only time that I have gotten paid is the week or 2 of Christmas. In the past, every family has taken this time off so I have not officially closed and therefore gotten paid. I am technically not closed though so if anyone wants to send their child any of those days I am available but no one has ever done this. I don't think I will be that lucky this year though and will likely have to take it off unpaid. I charge $10 less per day they are gone so really, as long as they have a back up provider, it is cheaper for them to take holidays different that mine. Every one has grandparents that provide care so almost no one ever has to pay someone else if I am closed as their families babysit for free.