when should running shoes be replaced?

Most running shoes should be replaced every 300 to 500 miles.

Because every runner has a different gait, surface preference, and body weight, this range can vary. It is helpful to look for these physical signs that your shoes have reached the end of their life:

• Compression of the midsole: Press your thumb into the foam of the midsole. If it feels hard, thin, or you see deep horizontal creases that don't bounce back, the cushioning has likely lost its ability to absorb impact.
• Worn-out tread: If the rubber on the outsole is worn smooth—especially in the heel or at the ball of the foot—you are losing necessary traction.
• Asymmetrical wear: If the soles are wearing down unevenly, it can affect your biomechanics and potentially lead to injury.
• Aches and pains: If you start feeling new soreness in your feet, shins, or knees after runs that usually feel comfortable, your shoes may no longer be providing the support you need.

If you track your mileage, checking that number is the most reliable method. If you don't track mileage, keep an eye on how your feet and joints feel; when those "well-worn" shoes start feeling like they are "dead," it is time for a new pair.