Check out these sites for good information, such as,
- When to buy new running shoes? Check out this link
- For help on how to buy them, go here
- This site has five mistakes to avoid in getting a new pair of running shoes
As for me, I think the 500 mile rule of thumb is good, but it depends on the runner. People who strike hard — as I do — many need to replace your shoes before 500 miles, while people who are very light on their feet might be ok to go past 500 miles. It also depends on your shoe. Shoes with less cushioning may have to be replaced faster than those with more.
Of course, if you are feeling pain or stiffness on older shoes, that may be all the information you need. That is happening to me now. I also look for creases in the cushioning in the heel of my shoe. Look at the shoe on the right above: you can see creasing on the heel. That’s a good sign that the cushioning is going on me.
(flickr photo from Siebuhr’s photostream)