I don't list my paid vacation in weeks, I list it in days in my contract ie. 4 weeks=20 days. I often will take 2-3 days attached to a long weekend, but not the whole week. So if my families pay for 10 days of my rest time, they will pay based on the days they attend when it overlaps with my vacation. In the instance where I have FT families, I might take full weeks, so their days paid to me, might all be used up in the summer, but I will continue to take days off during the year, and the part-timers will continue to pay until the 10 days have been used that overlap with my days off.