I dont sit for rover...YET.....just bought a house and need a fence. But i use rover consistently. I tend to tip about 5 dollars a day per stay (5 night stay = 25 dollars). Most of the people around me charge 30/night so 15% would be 4.50. But i agree, when i finally start sitting, i wouldn't expect a tip. I love these animals and that's why i'm doing it. I learn something new from all different breeds, etc. My dog gets friends out of it as well which is a plus since he's an only dog (thats a big tip in itself!)