We have received a bit of conflicting advice on when to neuter. Our breeder suggests 8-12 months; our vet says right away at 6 months. I'd be interested in hearing Hav owners' thoughts about this and their experiences.
Kodi was done at 7 months, because he had a skin infection that caused us to cancel his appointment at 6 months. (the vet said it wasn't safe to cut through an infection) At that time (7 years ago) 6 months was pretty standard practice, and it was actually written into my contract that way.
Now our understanding of puppy development has changed. While most of the studies have been on larger breeds, there is a strong correlation between early spay/neuter and certain very nasty (almost always fatal) cancers. There is also a lot of evidence that ACL and CCL ruptures are more common in dogs spayed or neutered before maturity. For this reason, most sport people are putting off spays until after at least one heat, and neuters until after one year of age. (a lot of people I know prefer to wait until two years of age for either procedure) Many breeders (including both of mine) have changed the wording in their contracts to allow more leeway in terms of when spay/neuter is performed, even in pet puppies.
That said, there are a lot of reasons that you might want to have it done earlier. An intact, sexually mature dog can be a handful, and if you don't want to deal with it, and train the dog not to mark and hump inappropriately, it is reasonable to alter earlier. Likewise, if you must use doggie daycare, most will not accept an intact dog over 6 months. Even those that will usually won't allow the dog to interact with other dogs. Also, if the dog needs to have another procedure done, like a hernia repair, cherry eye or having baby teeth pulled, it can be safer to only have to put the pup under anesthesia once, and get everything out of the way at the same time.
The bottom line is that there is no one "right" answer for all dogs in all families. Be informed, and make the decision that is best for you and YOUR pup!