For instance, if it fell on a Friday, we'd usually go until Wednesday--the 23rd. But if it fell on a Tuesday, for example, the last day would be Friday--the 21st. We would normally go back Jan. 2, but again, it depended on the day of the week. Our vacation would be 10-14 days and the length of it affected the day we started school and the day we ended--again taking into account the day of the week. I suspect most school districts do something like this.
In the early 1950s, when I was in the primary grades, we got a 3-day spring vacation in mid-March, but somewhere along the way, it got extended to a week. We used to go to school over 200 days a year.