What determines when you replace your running shoes?

Experts say it's not the number of kilometers that determines when to replace running shoes, but the wear of the midsole foam, the wear of the outsole and upper, and how they feel while running.

• Based on mileage (e.g. after 800–1000 km)
• When I notice visible wear on the sole or upper
• When they no longer feel cushioned or comfortable
• I don't track it — I replace them only when they fall apart