No matter how I'm doing financially, the Depression has never disappeared from my consciousness. To this day, I hate waste. When neckties went from narrow to wide, I kept all my old ones until the style went back to narrow.
I don't think humanity just replays history, but we are the same people our ancestors were, and our descendants are going to face a lot of the same situations we do. It's instructive to imagine how they would react, with different technologies on different worlds. That's why I write science fiction -- even though the term 'science fiction' excites disdain in certain persons.