Treat physical capacity like something worth preserving before you need it urgently.

Physical capacity behaves like an old house. The maintenance is boring, invisible, and easy to defer, and the day you finally notice the problem is the day the repair becomes expensive. Most people begin treating their body as valuable at the exact moment it stops being reliable, which is the worst possible moment to start. Preservation is cheap; reconstruction is not.

Pick one thing you would hate to lose the ability to do and protect it now, while protecting it costs almost nothing. Put it on the calendar the way you would a meeting you cannot move. You are not fixing anything; you are keeping something you already have.