Fact: Aging isn't always fun. But if you exercise pretty frequently and eat right, you might be a lot younger than you think — at least as far as something called your "fitness age" is concerned ...

The calculator tells me I’ll save just over $48. For two pairs, I’ll save 23.7% off what I’d pay for both at full price. Of course, the best way to save is to buy only the pair I truly need.