The way ours worked was that there was a yearly tuition, amortized monthly.
How much you paid for the year depended on how many hours/days. Their options were
9-12
9-1
12-3
1-3
9-3
M-F any combo of days
It was the same payment every month (because it was just the total divided by 10). We had *complete* control in whether we brought our kids in or not, but that didn't change the monthly rate. Just like college or private school. The tuition is due, regardless of whether you attend class.
All federal holidays were off.
2 weeks in winter were off
1 week in spring was off
2 months in summer were off (UNLESS you did the 1 month summer session)
The preschool closed for snowdays/ stormdays/ etc. following the public schools.
While those of us w/ Monday or Friday schedules LOOKED like we had fewer days of school... the school was VERY good about making sure that teacher work days and conferences were held tu/wed/thurs. So it all evened out. Each day of the week had an equal number of school days in it UNLESS there was snow!
Looked at ONE way...We didn't pay for sickdays... because there were 3 providers. 2 full time, and 1 float. If someone was sick, the float covered. Looked at ANOTHER way... we did. Because we paid the same monthly rate, period.
Looked at ONE wasy... We didn't pay for vacations. We paid for the months that our children were in school. Looked at ANOTHER way... we paid the same for December (2 weeks off) and March (1 week off) as we did any other month. I mean... they COULD have just made each month without a break more expensive... but that's just unnecessarilly complicated. The yearly tuition divided by 10 just made things MUCH simpler from a mental point of view. They had a grand total of 3 months of "vacation" each year (if you didn't pay for summer session), or 2 months if you did pay for summer session. But, again, it was just "easy", because is was $6,000 / 10... or $4700 / 10... or $8200 / 10.