Are you having sudden unexplained arch pain? Is there a strange ache in your knee? Are you wondering if you are losing your mind? Well, good news! You’re not going crazy, you probably just need to buy new running shoes!

I know because I just went through this. I’ve been running with no problems and then—WHAM!—all of a sudden I’m having strange aches and pains in my lower legs and feet. Of course, as an injury-prone runner, I freaked out thinking that I am on the verge of either a fracture or a nervous breakdown.

I’ve been running for years, but for some reason, I never remember when it’s time for new running shoes! It happens to me every time, and then I remember to check the mileage on my shoes. Palm meet forehead.

So how do you know when to buy new running shoes?

Here are a couple of ways:

Listen to your body.

Like I mentioned above, your body will probably let you know if you need new shoes. Mario Fraioli, senior editor at Competitor magazine, answered a runner’s question about new shoes in a Q&A: “Nagging little niggles in the form of sore arches, shin pain, achy knees or other small annoyances will start to manifest themselves when you’re not getting the support and protection you once were from your shoes.”

He says that while these aren’t real injuries, the persistent aches and pains could lead to injuries, so fix your footwear! If you’re not sure if this is what your body is telling you, “…go into a running store and try on a fresh pair of the same shoes you’ve been training in—assuming they’ve worked out well for you, of course—next to the old ones. If your old dogs feel flat and “dead” compared to the new ones, there you go. The best way to tell the difference is to feel the difference.”

Track mileage.

I use DailyMile to track my workouts. DailyMile has a nice feature that lets you attach specific gear to each workout. So, everytime I take my Brooks Adrenaline GTS 13‘s out for a run, I tag them so that I know how many miles I’m putting on them. All shoes are different, so it’ll take a couple times for you to figure out when your favorite model of shoe’s time is up.

For example, I’ve only been running in this particular shoe since August. My DailyMile gear-tracker said my shoes has 330 miles on them, but since I’d never been through a complete training cycle with the Adrenaline, I wasn’t sure if they were ready to be replaced or not. A simple Tweet to Brooks, and they responded letting me know that my pair of shoes should be replaced between 300-400 miles.

Aha! It was time to buy new running shoes! And like Mr. Fraioli said above, I could tell as soon as I tried on the new pair that my old pair was toast. Shoe brands and types (minimalist vs. traditional), running surfaces and body weights are all factors, of course, so mileage can vary widely. (Elite marathoner Ryan Hall, for example, gets new running shoes twice a month!) But for a general guideline, check with your shoes’ manufacturer.

Press Tests

Runner and New York Times columnist Gina Kolata says in the article, “When to Retire a Running Shoe,” that her coach Tom Fleming uses a press-test method: “Put one hand in your shoe, and press on the sole with your other hand. If you can feel your fingers pressing through, those shoes are worn out—the cushioning totally compressed or the outer sole worn thin.”

In the same article, Kolata cites Rodger Kram, a biomechanics researcher at the University of Colorado. His theory is that runners should change their shoes before the ethylene vinyl acetate (EVA), which is inside the soles of most running shoes, breaks down. “Think of a piece of Wonder Bread, kind of fluffy out of the bag,” he says in the article. “But smoosh it down with the heel of your palm, and it is flat with no rebound.” He says a moderate amount of cushioning is good for runners, but admits there’s no real proof that cushioning actually prevents injuries.

I don’t know. Cushioning certainly feels like it helps since my shins, ankles, arches, calves and knees complain when it is time to buy new running shoes. My husband also complains, but that’s a whole different blog post.