I left NATS at the age of 55....great idea. However, I was in the position to sell myself back to the company as a contractor............loads of advantages there, until I had repaired the hole I made in the lump sum.
As said above, no medicals anymore, worked by agreement (when I wanted to), no issues over annual leave, and best of all, not having to put up with all that corporate crap.
Finished altogether now, now regrets, not one.