They say that a dog who is neutered/spayed before reaching maturity will "never reach their full physical potential". If it is a pet, though, really....who cares. I have had many neutered pets, neutered sometimes when they were what most people consider too young because they were neutered at the shelter. I never noticed them to be physically defective in any way but they were usually mutts so how can you tell? If mine was just going to be a pet, I would probably spay by 8 months as why would you want to mess with that mess. Many standards often don't even come into their first season until they are close to a year old and I have known some to not come in until they were almost two. That is standard poodle though, the little ones I don't know about.