I'm 59, retired for two years now, and unlike the others, I don't foresee a time when I'll ever not want to have some kind of purpose in life. I don't think having purpose is a matter of age; it's a matter of personality, outlook, values, and philosophy.
However, it's also a matter of definition. I suspect many people just equate "purpose" with career and raising a family, and that's as far as their thinking goes.
My conception of "purpose" has changed through the years. In my early years, it was more defined in terms of work and career. By the time I reached 35, it had become redefined internally -- in terms of who I was becoming as a person, my learning and growth. That links to relationships. Later in life, I started to understand that following any of your values is a purpose, and I started to identify my values more explicitly, finding that I had quite a number of them. I understood that even something as simple as appreciating nature can be a part of purpose.
A central theme for me is learning and growth. The learning could be psychological, spiritual, intellectual, emotional, relational, or spiritual. Anything that takes me forward in any of those regards is "on purpose," as far as I'm concerned.
Anything that supports that is also "on purpose." For example, anything I do that supports my physical health is part of that purpose. Anything that supports my mental health is part of that purpose. Anything I do to take care of myself is part of that purpose.
Broadly speaking, my purpose is to have a happy, satisfying, fulfilling life. (When I say "happy," I don't just mean passing pleasures, although those are fine; I'm talking about enduring happiness or contentment). Anything that leads me there is on purpose. In general, that means trying to focus on what I value, what I think matters, and to avoid spending too much time/energy on things that don't.
However, having a happy, enjoyable life also means (especially in retirement) plenty of time for resting, relaxing, farting around, doing nothing in particular, staring out the window, playing games, whatever. All of that is also part of purpose. "All work and no play..."
So just to hammer that point home (because people invariably misunderstand) -- none of my purposes feels like "work" to me ("work" in the sense of drudgery, obligation, duty, something you're doing for external rewards). If something starts to feel like a duty or a chore, I just stop and move on to something else. I've already achieved enough in my life; I don't need to do anything more. I don't need to "prove" anything to anyone or myself. Anything beyond what I've done already is just icing on the cake, and I only pursue it if I enjoy it.
I like the positive psychology concept of using your specific strengths in an area that produces "flow." I do that through writing. Over the past year or so, I've created a blog and then written a book. I enjoy the process of writing, and I am proud of the work I do, although it is small potatoes in the grand scheme. It helps other people and honors what I think is important, and that feels good.
Since retiring, I've found the "frog on a lily pad" image useful. Instead of setting one big goal, I jump from interest to interest, just based on how I feel. I try to carve out small, manageable projects, rather than bite off more than I can chew. As long as it's interesting and enjoyable, I continue. When it starts to get old or boring, or I feel like I've said all I need to say, I hop to the next lily pad.
I could ramble on some more, but that's probably enough.
