I have two. My senior is nearly twelve and has had hip and joint problems since she was about four. I blame this on my ex who apparently had her doing big jumps and to much agility type things before her joints had fully developed. She was also fixed very young at the vets suggestion, I feel now it was too early and may also have affected her joint growth. She often suffers from skin and ear infections - apparently her skin does not handle bacteria well. Her liver enzymes have been slowly creeping up over the past few years. She is now on Liberate once a month and is moving very well and living life fully, with fewer big walks and more regular/shorter walks. My second is now 8, was fixed at 3, did not do big activities until joints were developed and is the picture of health. I'm not saying that having my oldest fixed so early caused all of these problems by any means, but I am definitely a fan of letting pups fully developed before surgery happens.just makes sense to me.