Late 40's here, and no, it never ends, but it does change. I've gone from asking whether or not I've made "good decisions" or even "the right decisions" and sometimes dwelling a bit too much on things I can pretty objectively say I fucked up, to the more holistic approach of reviewing past actions with an eye towards evaluating what worked and what didn't work so that future decisions can benefit from past experience.
A lot of it comes from spending quite a few years now in the business world. In business, there are always projects, major or minor undertakings in order to accomplish something. Some specific task with measureable results. You look at what needs to be done and investigate different options and weigh out the costs and benefits of each, but you also look at what worked in the past and what didn't. You adjust, you take into account how things have changed since then, and you don't make the same mistakes twice. When the project concludes, you review the entire process. Even things that went well are dissected because knowing what works and knowing what doesn't work are equally important.
Real life isn't exactly like business of course, and truly, you can suck a lot of the fun out of life by getting too hung up in the details. Trying to plan things out too much and not really enjoying what you're doing because you're thinking too much about it, because that's supposed to result in you enjoying things more, and it ironically has the opposite effect. But only idiots don't learn from their past. And to learn from it, gain perspective and experience, perhaps even wisdom, you have to look at it critically and evaluate things. What worked and what didn't. Not so you can sit and worry about it, or whine about things that could have been but won't now because of a choice you made; but so you can avoid feeling like that again because you learned from it.