I actually change the children at least once a day. usually after lunch. then they get dirty a bit after as well but parents take the children in and we usually wash their hands and faces before they leave. I did have one mom ask me to put smocks or something on her son cause he was coming home with some paint on his clothes (very little). I told her to provide me a shirt he could dirty and recommended that he doesn't wear his best clothes here. He is still always the nicest dressed.