I walk my dogs 2-3 times per day weather permitting, about a mile each time. They're extremely high energy dogs with extremely high endurance. Because of them, I've gotten in shape. Before I had gotten them, I never would have thought I could walk 2 or 3 miles in a day, but now it's a daily occurrence (and that's not counting all the play time as well.) Both of my dogs are young, about 2 and 3 years old, so they're even more high energy, but they don't get all their energy out just playing with each other. I think they need the walks as a sort of routine thing and to get out of the regular yard and see other things.