I've never neutered any of my boys who came to me as puppies, or as intact adults. Other than the fact I'm a responsible dog owner, I had no other reason why until the last couple years when research has shown the negative health implications. Had I known what I know now when I had Sophie spayed, I probably would not have done it. All of the spayed/neutered dogs we've had died from cancer. Only one of the intact dogs did, and she had a brain tumor when she was 18 months old.
I'm not endorsing doing it or not doing it. I think it's up to each individual dog owner to decide what's best for their dog.
Now to answer your question, I'd wait until at least 2 years old to make sure full maturity and growth plates are closed. Your breeder should be able to give you a reasonable idea of when their line mature. I had Sophie's spay done when she was 22 months, she'd was 3 months past her 2nd season.