I also change every 2 hours and, of course, anytime someone is poopy.
Question though, for providers who are outside at pickup time - how do you handle playing outside AND trying to make sure kids go home with clean/dry diapers? We are outside from 4-5/5:15 based on the last pick up and all the diapers are changed at 3:30 after snack. The ones that go home between 4 and 4:30 don't need to be changed but my last kid always needs to be changed around 5. So, I end up bringing him in and changing him and then just staying inside - when I'd rather stay outside until all the kids are gone! How do you do it?