I don't charge for my holidays either. I do, however, charge for the odd day here and there that I may close. My families pay upfront for the entire month and it's cheaper (I hate that word ha ha) to just pay the full monthly rate, than for me to pro-rate. I give at least 1 month notice to close a day, other than a stat, and at least 3 months, if not more, for summer holidays.