I was wondering about this. Buttons (11 weeks) will chase after Biff at the park and never stops for a rest. Should we only let her run after him for so long?
They can play as much as they want. There is no reason why you can practice your recalls and have them sit for a minute before letting them go off and play again. It is good practice to call them too you and let them go off and play again. That way they won't associate the recall with the end of play time.