It's most often a form of "well this is what I wish I'd done when I was in a similar situation years ago" or "here's what I did when I was in your position and let me tell you how great a choice it was." That is meaningfully distinct from and a lot more common than the much more useful version "I once had something similar happen and afterwards concluded that I should have done X, but the world has changed over the decades and now it seems like kX would yield better outcomes based on Y."