What was the best life hack you discovered too late?

That by reading Hacker News I do lose any semblance of self respect for myself.

OT but hope some here may use this to their advantage. Years ago news reports highlighted excessive amounts of sugar & salt being used in commercial food production. With that knowledge I decided to no longer ADD those ingredients to my diet. Now regard that decision as the most important for my continuing longevity!

You can live beyond your means by buying used and learning how to repair broken things.

Needle and thread, solder and glue, these things can stretch almost any income.

Also, get and understand your credit score. Having good credit takes time and effort but pays back in life ease once you make it.

Travel, a lot, when you are young. You're not going to have the energy to do it when you're over 60