Riker is 5 months old. On a regular weekday he gets:
He gets 2 30-minute leash walks a day
A bunch of small walks for pee breaks (we can't go in the back garden right now)
At least an hour at the dog park where he can go as crazy as he wishes
Probably about 45min-hour/day playing fetch with his ball or chase the laser pointer (I usually do most of the playing right before bed to get the last bit of energy out)
On weekends we usually go on an additional long hike in the forest off leash.
He behaves like a monster no matter how much exercise he gets
But he sleeps a lot more and has better obedience focus when he's tired out!