"Good shoes take you good places."
How often are you replacing your running shoes? Although there are a lot of factors that go into the life of a pair of shoes (running, walking, cardio machines, dance fitness have different impact levels), the rule of thumb is that your shoes will last between 300-500 miles. But don't forget about the general shelf life of the materials, not that shoes are going to fall apart 9 months to the day after construction, but seams and adhesives do deteriorate with time, something to consider when you are buying an older "model" at a discount. Consider this your reminder to give your workout shoes a checkup!
*I tend to run errands before or after a workout, so I always keep an extra pair of shoes in my car, and dedicate my running shoes to workouts only.
*Whenever I buy a new pair of shoes, I set a reminder on my calendar for 5 months to start paying closer attention to how my shoes (and knees, feet & hips) are feeling. Having suffered plantar fasciitis and stress fractures, paying attention to the condition of my shoes has become a priority.
*When shopping for new shoes, bring your old ones to compare...feel them, bend them, squeeze them...you might be shocked!