Most people agree that regular running shoes should be replaced every 300-500 miles and say that minimalist shoes may need to be replaced somewhere between 200-400 miles. The real answer is that it depends. It depends on your mileage, the surface(s) you run on, your weight, and also on the way you wear down your shoes.
Some people start to notice that their feet or knees are a little more sore as shoes get older, but how else do you know when it’s time for them to go?
If you keep track of your runs in a log, note which shoes you are wearing as well. When you get into that 300-400 mile range, see how you feel. Check your shoes to see if the sole is starting to fall apart or if the grip on the bottom is worn off.
Some runners change their shoes when they hit a certain number, while others can go twice as far than the recommended mileage.
To extend the life of your shoes, you might want to get two pairs and rotate them. You never want to head out on a long run in a new pair, so if you break in two pairs and switch them up, they will last longer.