I think Ralph is right to a limit. To an outside observer, I would appear to be in my productive years. I'm in my mid-30s, have been out of school for some time and am gainfully employed. I wouldn't disagree with that, but in so many ways I still feel very formative. The biggie is how my hobbies have changed. From my mid-20s to my early-30s, my primary hobby was going to live music. I'd go out locally three or four times a week, and I'd fly to cities just to see a show. That started to change a year or two ago. Now I'd say my main hobby is hiking in the Adirondacks, something I've only been doing for nine months now. Instead of scanning tour pages for dates I could make, I look for a time to get away to the mountains. So professionally I've moved from formative to productive, but I'm also reflective about my time city hopping and formative with hiking and backpacking. I think Ralph was right for individual things, but overall I think we can be formative and productive forever.