We had a Golden, Sunshine, that we took in at age 9 many years ago when her owner died. She had never lived indoors (she had lived at her owner's lake house), and she made it very clear to us that she was NOT going to come inside our house, no matter what the weather. Our vet told us to leave her alone, since she had done fine up to that point. We figured that she was near the end of her lifespan after reading up on the breed. Well...that old girl lived to be 17! We were stunned, to say the least.
We also had a lab, Chipper, who lived to be 14 1/2. We were amazed with him, as well, since labs don't generally live that long. He finally succumbed to vestibular disease that he couldn't recover from, despite vet intervention.
I'm a boxer lover, and I know they come with a laundry list of genetic and behavioral issues (cancer and heart issues being the biggest killers). After losing a few boxers to various health issues, I decided not to own any more of them. Of course, sometimes the best laid plans... I adopted a senior boxer, Jackson, from the pound last summer because he was on the "very urgent" list... I have no idea how old Jackson really is (at least 8, according to my vet), nor his past health history. He has arthritis in his shoulders, which is currently being managed with Metacam, but he seems otherwise healthy, and has plenty of energy for us (anyone with a young boxer knows how insane they are!). We treasure each day he's with us, but we know that he could easily take a turn for the worse at any time. At least he'll enjoy his last few years in comfort!
RESPONSIBLE and EDUCATED breeders will do breed specific health testing on their breeding stock and cull out dogs that produce litters with genetic issues. However, all the back yard breeders and puppy mills out there are making it all but impossible to eradicate these killer diseases, IMO. Sad...