Shoe lifespans vary, depending on how much they are worn. Sneakers should be used for running on average about 300-500 miles, according to Runner's World.
To determine if your shoes need replacing, put your shoes on an eye-level, flat surface. Podiatrist Dr. Jackie Sutera calls this the "tabletop test." If the shoes don't rest flat due to worn soles, they can cause pain or potential injury (per Footwear News).
Dr. Velimir Petkov, a podiatrist with Premier Podiatry, also suggests looking at the midsole, or cushioning part. Cracks or wrinkles in this area are a sign that the shoes can't provide as much comfort and support. Even if you don't spot any damage, pay attention to how you feel during and after you wear the shoe. Shoes that hurt your feet are a red flag that it's time for an upgrade.
Maybe the shoe is fine, but your foot changed. According to Dr. Joy Rowland, a podiatrist with the Cleveland Clinic, feet get longer and wider due to changes in ligaments and tendons. For pairs that you've had a long time, make sure they still fit. Avoid the damage of wearing too-small shoes.
While you're investigating, check your shoes for any funky smells. Many times these odors can be eliminated through the power of baking soda, a disinfecting spray, or a trip though the washing machine (per Good Housekeeping). If the odor can't be banished, say goodbye to the shoes (and the bacteria).
