• When to replace running shoes depends on the runner.Beach runner image by Evgeny Berdjansky from Fotolia.com
  
  

Mileage is a Good Indicator

• According to Milan Running, "Most runners agree that a new pair of shoes is needed every 300 to 500 miles." The company recommends keeping track of your daily and cumulative mileage so that you'll know when it may be time to purchase a new pair of shoes.
  
  

Other Factors Affect a Shoe's Lifespan

• The Runner's Guide notes that some runners need to replace their shoes more often for a variety of reasons. Heavier runners as well as those who strike the ground hard often experience shorter shoe life and may need to replace their shoes more frequently.
  
  

Bottom Line

• Milan Running recommends using your running log as an indicator and monitoring your shoes for signs of wear and tear. Creasing in the material under the heel or near the ball of your foot indicates that your shoes are worn out. If you're unsure whether your shoes need to be replaced, try on a new pair of shoes. If the new shoe is much more comfortable or provides more support, there's a good chance that it's time for a trade-in.