Our Maggie was diagnosed at a very young age as having severe bilateral hip dysplasia, and now her elbows are getting compromised from carrying so much of the load, and she has spondylosis. She has good days and bad ones, but on her good days, she is a sassy, bratty, IN-your-face, muffin head, and we love her dearly.
Lucy, our landseer, was diagnosed at her routine cardiology screening (at 2 years) as having "tricuspid valve dysplasia". We had a board certified vet cardiologist do a color doppler on her. The valve never comes close to closing. At that point, there was always at least a 1/2 inch gap through which the blood "regurgitated" (backwashed). Since then, the gap has probably widened, as her heart has enlarged. The vet didn't think she would live very long...but she just turned 5 on Christmas Eve. She is our sweetheart and serious "mommy's velcro dog"...even sleeps in the bed with us some nights.
Brenna, our rescue girl, is pretty darned healthy and solid, but she's got a huge barrel of a chest, so I do worry about the possibility of bloat. We feed two small meals a day and keep them all very lean.
We just treat them all as normal dogs, but do what we can to keep Mags and Lucy from over-tiring themselves. None of us knows the number of our days, so every day should be lived as if it might be the last...so we just enjoy our girls and give them the best life we can.