Now retired. The moves were in the same field (education - I'm a one trick pony) - first to the private sector and then onto a university. Same field but in many ways a different world and I loved it (mostly). It meant I finished my career doing something that I wanted to do rather than just...
Not a radical change, but I reached my early 50s thoroughly fed up with what I'd been doing (teaching in a failing FE college) for the previous 30 years and simply hanging on for retirement, treading water and being generally miserable. I took a punt at a change of employer in the roughly same...