I suspect many adults don't plan ahead either, but rather remember advice for later, once they've personally run up against the problem the advice solves. How many people poured money into the stock market despite their grandparents' warnings that stocks can go down as much as up? Or bought massive houses with no money down despite warnings about taking on too much debt? Or started businesses despite all the common wisdom about how you're basically guaranteed to fail your first time?
Before I started working on my startup, I worked for 2 other ones so I could see how it was done and hopefully avoid their mistakes. Despite carefully taking note of everything my past employers were doing wrong, I made all their mistakes anyway. The difference was that I could recognize it as a mistake in a week instead of spending years going down a dead-end path.
This may even be the smart way to do it. Every time I've blindly taken advice, it hasn't worked out. The situation's always more complex than someone's 5-minute soundbite, and having personally experienced the problem seems to be essential for making sense of the advice and picking out the parts that are relevant to my particular situation.
