Mia has extreme ball drive and loves for us to kick the soccer ball or play frisbee. She would play nonstop for hours if I let her. We also incorporate obedience while we play (sit, wait, back up, and down) Her focus on the ball amazes me. Never takes her eyes off it if the whole time and really tenses up with anticipation before we kick it. Anyway, my question is, how long should I let her play ball when we're outside? I do make her take short breaks which she hates. She's 18 1/2 months old and in good physical shape. She's one of those dogs who just never seems to tire when we're outside. Took her on a 7 1/2 mile hike last fall and she led the entire way. Acted like she could have done another 7.