answer:It takes way longer to wear out than to rust out. Exercise is the number one key. For the body, work out regularly. You need at least 3 days a week of good, aerobic exercise. If you want to retain strenght as well, alternate between aerobic and strength routines and work out daily. Check out this septuagenarian. And exercise your mind as well. Read, write, surf, intreract, work crossword puzzles, find new passions and study them till you are reasonably proficient in them. If you don’t use it, you lose it. Eat a healthy diet with lots of fresh vegetables and fruits. Get adequate sleep. Stay connected and active with people. You’ll live much longer if you like living each day. Of course, there is a strategy of being miserable every day. You won’t live nearly as long, but it will seem like an eternity. Stay well, all.