If you are a runner, you should replace your running shoes every 3-4 months or 300-400 miles, or sooner if the soles show signs of wear. This ensures that your shoe continues to offer your foot–and as a result, ankle, hip, knee, and spine–adequate support and shock absorption. This will help reduce the likelihood of injury as you train and also if you are a recreational runner. It’s also a good idea to wear your running shoes exclusively for running to extend their life. You can keep your old shoes or buy an inexpensive pair for everyday use in your yard or around town.