My mother in bed at fifty-two. My mother in bed at sixty-eight. When I lay the two images of her side by side, looking for the differences, at first there seem to be few. She was older, thinner, more wrinkled. Her hair, late to gray, was now sprouting a few silver strands here and there. These differences were subtle but present. Harder to spot: me at eleven - out of my depth; me at twenty-eight - still so.

All of this is natural. But along with the natural ebb and flow of life, each of us has a habitual approach to friendships. Often this approach is less than conscious, close to automatic. We give our friendships whatever feels natural to give them, rather than considering what they need. As we get older and life becomes busier, we have to make decisions about the limited time we have, and our friends often come last.

We found scant evidence that the people in our study had an explicit goal of working until a target retirement age to be followed by a life dominated by leisure. The vast majority of people in this study remained engaged in some permutation of a hedgehog well past the age of 60, in some cases into their 70s, 80s, even 90s. That said, nearly half the people in our study had a “retirement” from one hedgehog partway through their lives and faced the challenge of transitioning to the next one. Sometimes these were relatively smooth transitions, such as Tenley Albright’s shift from skating to surgery.

I also take solace from Franklin’s life, in learning that he endured an extended trough in his 50s and 60s (relative to the rest of his life). If Benjamin Franklin can make mistakes and misjudgments, then I don’t feel so bad about my own mistakes and misjudgments. If Benjamin Franklin can spend years on efforts that ultimately ended in failure, then I don’t feel so bad about my own efforts on projects that ended up being dead ends or cul-de-sacs. If Benjamin Franklin can feel dispirited and in a fog funk, then I don’t feel so bad about my own existential fog funks. If Benjamin Franklin can enter his 60s with half of the most significant pages of his life yet to be written, then I feel quite good about the possibilities for the late decades of life.

In writing about Benjamin Franklin and casting back through all the remarkable people in this investigation, I’m struck by the imperfections in their lives. The stories led me to a gigantic, calming exhale about my own life imperfections, letting go the anchoring weight of past mistakes and missed opportunities. I take from studying them a reminder that I wrote for myself and that I return to whenever I find myself being pulled around backward in the saddle by past regrets: You cannot straighten out the road behind you.

I have spent many years judging my dad’s performance as a father. I have spent much less time considering what it took for him to keep going, and to give me what he did. He knows I’m writing about him, and about the things that went wrong and the places where we both fell short. Opening up in the way that he has a radical act of generosity.