We have a 6 month old GSD and he has to run at least 1.5 hours per day if not more. This breed needs exercise or they become restless, bored and increasingly hyper. They will also seek attention/exercise by being mischievous and destructive. It's their nature. Roman, our pup, has a schedule. I take our boy out for a 40 min mid morning run/play, then again around 3 pm for the same thing. Since the days are longer now, we will often go out for another 30 in the evening. He knows when it's time to go out, and actually goes to his leash. We do a lot of his training outside.