What do you mean by health guarantee? Ask for specifics.
Do they mean that the puppy is coming to you without any illnesses? If so, I think most states only require that guarantee to be 3-7 days because illnesses can be picked up on the trip home or shortly after getting to your place.
Do they mean congenital defects? If so, do they limit which ones? Do they require you to return the pup? Do they offer to pay for surgery if needed? If so, is there a limit to how much they will pay? What if the dog has a second problem after that?
Some breeders guarantee their dogs for life. Find out what that means too.
And most of all, make sure any breeder you are considering does health testing of both the sire and dam before they breed them: BAER (hearing), CERF (annual eye exam), patellas, and hips. Health testing can be verified online (http://www.offa.org
), but you'll also need the registered names of the dogs to search for the results.
At least with health testing done prior to breeding, you know the breeder cares about health and congenital defects not being passed along.