Whether you are a marathon runner, weekend hiker, or active mother your sneakers get worn out over the course of time. The length of time may differ but the amount of miles you put on a sneaker determines the age of that shoe. Mileage can break down the cushioning and stability of the shoe and allow for less shock absorption over time. Your legs and joints will begin to feel the impact and injuries may occur due to extra stress placed on them.
Your shoes are broken down into 2 major parts, the midsole and outer soul. The midsole, where the cushioning and stability is provided, usually is the first place to show signs of wear and can cause the most harm. Creasing of the insert will begin to show as well. The outer sole which is usually made of a carbon rubber is more difficult to wear down and will show wear in the later stages. It is only a matter of time before the outer sole has worn through to the midsole creating an uneven surface of the shoe.
You ask “how long does it take to wear out the midsole?” and the answer is usually 300 to 400 miles. Each person is different on the amount of time it will take to reach those miles. The surface of which you wear the shoe plays a huge role. More rigid ground with rocks and sand will wear out a shoe faster than that of a smooth and flat surface. Very active people will perform 300-400 miles in 3-4 months where less active people will lean more towards 6 months. A piece of advice is to sharpie the date you bought the shoes on the tongue. Give a glance at the date and think about how many miles you have gone since. If the mileage is over 400 it is time to replace!