When I had my own office, I gave 2 weeks per year, eligible after 6 months of employement.
I gave paid time off for the "Big 6" - New Year's day, Memorial Day, 4th of July, Labor Day, Thanksgiving and Xmas.
In my current office (large clinic) they get about 2 weeks per year PTO, but it's based on hours worked- each hour worked give a % of a PTO hour. So I believe it's something like 100 hours worked = 8 hours PTO. They also get the Big 6, but they have to work the work day before and the work day after to get the pay. So anyone who doesn't come to work this Tuesday won't get paid for Labor Day.