i think that there is no harm in playing with a puppy as long as the puppy wants to play, i think a puppy is the best judge of how much exercise is good for them, and i think that being tuckered out is good for dogs, as far as helping them to be content and not anxious, and not getting into anxiety related mischief. When a puppy tires of playing, he or she will stop, and when they need sleep they will sleep, so it's not necessary for the human to structure the time for the puppy. A human may want to structure time for human reasons, no problem with that, but i don't see a need to stop playing with a puppy who still wants to play, if the human is still willing to do it with them. I think many pet dogs get too little exercise rather than too much.
when i first had zack, he stayed in his crate with the door closed at night while i slept and while i was at work during the day. later, he had an X pen surrounding his crate with the crate door open. I always put toys in, safe ones that he couldnt' choke on. Now he has the whole kitchen to himself while i sleep, and he has the whole house to himself when im at work, or the downstairs part anyway. At night i put two or three toys in the kitchen, but it's my impression that he never plays with any of them. It seems like they haven't been moved when i return. But he does play with toys while he's loose in the house while i'm at work. He has access to all his toys when he's free in the house, but they're all safe ones.
maybe it depends on the dog, or maybe it depends on the human. For me, with zack, I've always thought he could decide whether he wanted to sleep or not. He has plenty of time to sleep so im not worried about him getting enough. i'm more worried about him not having enough activity and becoming bored, and that's why i put toys in the kitchen with him even though it seems like he doesn't play with them. I feel alright about him making the choice about whether to play with them or not.
