We don't have a pet, but there was a pet door out to the garage when we bought our house. One of these days, we really should replace that door. But until then, it sure is useful when Kate wants to check up on what M's doing out in the garage. She is very disturbed by lawnmowers and always points at ones that are running and says, "Owie." So this way she can see what he's up to when he's doing yard work without actually risking contact with the evil mower of pain and destruction.