Ask HN: What is it like to be old? What advice would you give to younger people?
Physically, my best advice is to take good care of your back and your teeth.These 2 things can make a huge quality of life difference once you are past 40. I would also add your eyes, but there is not a lot you can do about that one! Almost everyone needs reading glasses by 40. Glasses suck, but you get used to it.Psychologically, the best I can say is to forgive yourself for any stupid things you did when you were young. Try to be as kind to yourself as you would be to others. I think of this as the "inverse golden rule." Really important as you get older, because regrets and self-doubt pile up otherwise.