We pay monthly tuition regardless of holidays, sick days or our vacation days. However, daycares typically take few standard holidays (New Year's Day, Memorial Day, July 4th, Labor Day, Thanksgiving Day, some also take day after Thanksgiving, some take Christmas Eve, and Christmas day). Most seem to be open MLK day, President's Day, Veteran's Day, etc. All the schools in our area also close for one full day sometime around August for their teachers to take the state mandated training courses to renew their licenses, and that's just anotherday that has been paid as part of the tuition. We don't get credited back for it or anything like that.
My daughter's school has a summer program for June - July during which time there is the option to pay a weekly amount for just the weeks planned to attend. The weeks have to be scheduled in advance, and the cost works out where it's only more economical to pay a weekly amount if the child will be gone for 2 full weeks. My daughter's school also closes down entirely for two weeks at Christmas, matching the public school. We still pay for the month. They do NOT close down for Spring Break. I'm looking at a new school for her, and it does not close down at Christmas break or Spring Break. Her previous school also did not close down for those times. The new school does offer 5 days vacation time to the kids (meaning parents don't pay for a week when they're gone) after one year at the school.
From your post, I can't tell if you plan to close down to take a vacation for yourself and want to have that included in the tuition being paid. I'd say that might meet with some resistance from the parents.