Build an App to Tell You When to Replace Running Shoes

Worn-out shoes are one of the sneakiest causes of running injuries — but the “when do I replace them?” question rarely has a clean answer. Instead of hunting the app store for a shoe tracker that almost fits, you can build your own in a few minutes.

Why build your own instead of downloading one

If you search “app to tell you when to replace running shoes,” you’ll find plenty of options. Some are genuinely good — general shoe mileage trackers like a shoemile-style logger will count your miles and warn you at a threshold. That’s useful.

But most of these apps assume one number fits everyone (usually 300–500 miles). Your reality is different: you might rotate three pairs, run mostly on trails, weigh more or less than average, or care about how your gait is changing as the foam breaks down. A generic “track my shoe, know when to replace shoes” app can’t quite capture your situation.

When you build it in Auto, the app fits exactly what you run. People have already built exactly this — the Sole Check Frame is one real example — which is proof the idea works.

Build it in Auto

Auto is camera-first: you describe what you want, snap a photo, and it builds you a personal mini-app (a “Frame”) around it.

1. Open Auto and describe your goal. Something like: “Build me a running shoe wear analyzer that tracks each pair’s mileage and tells me when to replace them based on wear.”
2. Snap a photo of your shoes. Point your camera at the outsole and midsole. Auto uses the image to look at tread wear, midsole compression, and heel breakdown — the physical signs a mileage counter alone misses.
3. Tell it how you run. Add your typical distance, your surfaces, and how many pairs you rotate. This is where your Frame becomes yours instead of a one-size-fits-all tracker.
4. Set your replacement logic. Ask it to flag a pair when either the mileage or the visible wear crosses your line — and to nudge you before a big race so you’re not running an event on dead foam.
5. Log as you go. Snap a fresh photo every few weeks to watch gait-relevant wear patterns develop over the shoe’s lifespan.

The whole thing takes minutes, and you own it. Want to tweak the mileage threshold or add a second pair? Just tell Auto.

FAQ

How does a photo tell when to replace shoes? Auto reads visible wear — flattened tread, compressed midsole foam, uneven heel wear — which reflects real breakdown better than mileage alone. Pairing photos with your logged miles gives a fuller picture.

Do I need to know how many miles my shoes have? No. You can start from today and log runs going forward, or estimate your current mileage. Your Frame works with whatever you give it.

Can it track more than one pair? Yes. Tell Auto you rotate several pairs and it’ll track each one separately, so a mileage tracker built for a single pair won’t leave you guessing.

Is this better than a dedicated shoe tracker from the app store? Not automatically — but it fits your running exactly, and you can change it anytime. That’s the trade-off: minutes of building for an app that’s actually yours.