I have deteriorated cartilage in my right knee that requires care on my part to avoid a painful flareup. I have to avoid vigorous exercise early in the day and can't carry heavy items. It's annoying, but livable, as it's fine when fully warmed up. Every few weeks I forget and do something stupid, though, and have a painful knee for a few days. Had arthroscopic surgery done on it in 2000 which helped, but will probably need the knee replaced eventually.