I shifted to occasional, part-time work at 45, and am completely retired at 52. I have too much to do to have time for work!
I guess the key question is, do you know what you will do with your time? If you do, you should be trying to 'retire', i.e. achieve future financial security, as fast as possible. I achieved this by building my own house, learning the skills as I went along. Personally, I knew what I would do after my working life was over when I was 18, but I guess most don't.