Myself, I count lucky I was able to retire at 56. I found not much desire to stay in the books and keep as up to date as I required of myself. This argument of experience doesn't cut it with me, after 15000 hrs in command how much more can you get. At 45 I was on the top of my game and slowly downhill after that. I've seen alot of guys happy with the 60+, but most of them had no retirement skills.