I retiredc the first time at 40. It was a bit involuntary as it involved becoming slightly disabled but more than enough to end my career. I had enough to live comfortably on and all the bills were paid with some "play" money left over.
I thought it would be great to forget about going to work, get up when I wanted, play on the computer all day, etc. That lasted about 4 weeks. By 6 weeks I was climbing the freaking walls. I went back and hit up the HR office and asked about secoondary career training since my first was no longer feasable.
After about another month I was back in school going for a MA in ED and teaching cert. for my state. It really got to me that school was now fun and easier than it was when I was 18 - 21. After 3 years teaching I told myself, Self you STUPID idiot get outa there!!!! I then went to work directing a non profit education incentive organization basedon aviation. It was cool for 2 years then the boss got to be real hard to take. You can tell a fighter pilot, you just can't make him believe it.
I "pulled the pin" on the Army Reserves in 2000 and retired when the Wife had her reconstructive surgery from cancer. She needed me home more than the Army needed me and I couldn't have a second "bad" year in the Reserves.
I went back to school and got my A&P. School is still fun and easy but the some of the recent HS grad "kids" in the class with me were a bit hard to take. I already had working experiance and my own bird but they "knew it all".
I worked in GA until I retired again when the wife retired last June. Now I am enjoying not working and can deal with it. I have plenty to do to keep occupied and there is a big country to explore. Best of all every night I sleep in my own bed no matter where I am.
Retiring to a porch and rocking chair is a death sentence that is being carried out slowly and with malice. Don't do that, do something that makes it worthwhile to get up in the morning.