I could retire comfortably in a few years, but my earning power is at it's peak. Every extra year I work provides significant extra resources for my family, to help the girls afford their first houses and get a good start in life when they graduate. I'll probably work another 5 years beyond what I'd probably do if it was purely about self-interest for myself and my wife.
I'm lucky that I enjoy my work, so it's not a massive sacrifice, but I do enjoy my leisure activities more. I'm really looking forward to being able to go somewhere interesting in the world with the missus and just stay there for 6 months. Also I'm a Brit here in the UK so health care is just not really an issue.