Physical capability is freedom you carry without putting it in a bank.

Being able to move, lift, walk, and travel without arranging your life around limitation is a kind of freedom you carry with you. It cannot be stored or transferred, and no amount of money reliably purchases it back once it has gone. It is one of the few assets that is entirely maintained through use.

Treat some of your weekly effort as a payment into that account. Not for appearance, and not for a number. For the range of choices you want to still have when you are older.