We watched the same little pup (miniature Jack Russel) for over 5 years and recently started watching some friends dogs as well (a Great Dane & Boxer). All of this to say, we are used to a variety of sizes and personalities. One of us will be home everyday and that allows for us to be able to let the dogs out as much as they need during the day. We have a fenced front yard and backyard. We are close to open space and a dog park as well, so those are very much options... as well as dog walks, of course!