If you care for a medium to large breed dog well enough to get a healthy teenager for any period of time, you have done well. I've mostly had Dobies and Rott's, the average life expectancy is around 8 years for these breeds. My last Dobie, Kato, made it 14 years before I had to put him down, I sobed like a bitch and held him on my lap for an hour after he passed, I wanna cry just thinking about it. Ruger will be 8 this summer and he's healthy as a horse. I think the biggest key to a raising a healthy old dog is doing your homework when getting the pup. Look hard at the parents (and the parents litter mates if you can) if you can't meet with mom and dad, don't take the pup. Look at previous litters too if you can, most owners will be glad to have you visit. Stay away from pet stores and kennels, besides supporting puppy mills, those dogs are not as healthy as a private breeders stock. If you don't want to do all the leg work, adopt. Not trying to jump the thread, just a hard core animal lover, currently have 1 dog, 1 cat, 2 birds and a horse. Food donations are appriciated.