I'm literally right behind you. Next week is my last at work. Capping off over 43 years in the nuclear power field. I could stay longer - it's been a challenging and rewarding career. I enjoy the work and my coworkers, but I enjoy my free time more. I feel that the years from 60 to 70 are likely to be the best combination of free time, energy level, health, etc. and I don't (currently) want to spend any at work.
I've tried to prepare for it by recognizing:
1. I've never been retired before, it'll be different than I expect.
2. It'll be like starting a new job, so I'll need to learn and adjust.
3. I may, like others have said, find I want to be in the workforce again, so I've already got contacts with a few possibilities (who are eager to put me to work if I choose).
4. I'm avoiding any other major life changes or commitments.
I'm at the Wintergrass festival right now and having a blast as always! Really looking forward to a LOT more time for music!