Experience should have nothing to do with the fact of HOW one prepares for breeding. Whether or not nothing has shown up in ones lines, the proper health testing, screening, STD testing, BAT, ect. should always be done. It is a bit costly but having the assurance of a great bill of health in producing healthy puppies is worth it! A 48 hour health guarantee is not a health guarantee, what is going to show up in 48 hours? Even a through vet exam can't provide much piece of mind in 48 hours. As Rose has already stated, reputable breeders will stand behind their puppies guarantee or not! If you are having mixed feelings, look elsewhere. Great that you are doing your homework. Good luck in your search!