Just say NO unless your mutt develops traits you find undesirable then decide.
I agree with this. No reason to do it if you keep your dog under control, and he's not showing problematic behavior (or having medical problems) associated with high testosterone.
That's the way I've always done it. My male Doberman (gone since 2001) kept his till he was middle aged and started pissing blood. Vet said it was the high testosterone that was causing it, and it could lead to serious issues if he wasn't neutered, so I agreed.
My Pitbull (gone since 2011) kept his for about three years. Fixed male dogs would see him and attack him for no apparent reason. Vet said it was because he was intact, and they could smell it. He said fixing him would solve the issue. It didn't.
My Old English Bulldog (now middle aged) kept his till he was three. I finally agreed to have it done due to his constant obsession with humping my female half Pitbull (now 12.5 years old). It was making life miserable for her. His harassment of her went way down afterwards, even though he still occasionally tries to mount her. Not nearly as much, though.
