I've had my share of beat up athletic shoes in the closet, haven't you? Are you unsure about when to replace them? Do you wait until the insole falls out and the logos peel off before you consider buying a new pair? Actually, experts say you should replace your walking and running shoes every 300-500 miles depending on your weight, length of stride and frequency of usage. Even when the outside looks okay the good cushy stuff in the soles may be shot. If you walk three miles, four times a week, that's twelve miles so you'd need new shoes about every nine months. If you are an avid runner logging 45-50 miles a week you will need a new pair every couple of months. I try to replace mine when the time changes because my workout routines usually change then as well. How often do you replace your shoes?