JenniferRM:

In the meantime it seems like there is potentially a lot of prosaic stuff of the sort that various old people would like to tell young people about how "not to make the retrospectively obvious mistake I made" with respect to actions at 20, 25, 30, 35, 40, 45, 50, 55 and so on. Each of those ages makes me think of distinct sets of life challenges that I have relatively little personal experience with, but I imagine they could go a bit better if I did a little prep work in advance, guided by grounded data.

In my experience, when it comes to sincere advice from older folks, it's extremely difficult to separate the wheat from the chaff. This is both because the world is changing very rapidly these days and because, contrary to the usual saying, most people's hindsight is very far from 20/20. People are often oblivious to how much things have changed since their youth, and unable to distinguish true instances of correct and incorrect planning from random luck.

A huge problem here is that honest reflection about one's past mistakes, missed opportunities, and suboptimal decisions tends to be very painful and unpleasant, and people consequently prefer to tell themselves (let alone others!) a highly distorted and idealized story of their life and accomplishments. When they're giving advice, this problem is exacerbated by their additional propensity to signal respectability by telling an idealized story about how things should work in an ideal world, not an honest-to-God cynical story about how they really work. (For which I can't really blame them, considering how often the latter would sound crude and offensive. Of course, as with most human hypocrisy, this idealization mainly happens at unconscious levels, not as conscious deception.)