
My crate is 24w x 36l x 30h for my 68 pound Lab and I wish it was a fair bit bigger so he could stretch out better and move to find a cool spot once his body heat warms up the spot he is lying. Common knowledge at the time dictated you put dividers in the crate to make it smaller when puppy was little so all puppy could do was stand up, turn around and lie down again. I will never, never, never do that again. I will leave it full size so that inevitable time when puppy pukes, pees or poops he isn't forced to sit/lie in his own stinking, wet, waste. Unless you have no demands on your time like traffic, work, family the time Will come when you just don't get there in time to let puppy out.
Actually, I did not leave puppy in the closed door crate for very long at all anyway. I put the crate with door open inside a bigger pen or most recently in our gated kitchen. That way puppy can move his joints, stay out of his pee, and engage a bit more with the household from a still safe spot. My Vet believes too long crate time contributes to UTI, joint issues and neuroses. It would make a good study for a Vet student. Puppies can wreck kitchens, we were lucky, ours did not chew cabinets or walls or table legs. My sister's puppy permanently re-modelled the canon ball feature on the legs of her kitchen table.