I take less time off in the summer. Just the federal holidays. Summer heat and I are not friends, anymore, and lawn/garden/home maintenance takes up the majority of my free time, then.
I take most of my vacation time in Mid Spring and Early Fall.
I also (usually) take the week of Christmas.
I "don't charge" for my vacations, but that amount is already figured in to the annual tuition rate. When I cancel a vacation I actually make extra income.