Here's Exactly When You Should Replace Your Running Shoes, According to Experts
Worn-out shoes often equal injury. Find out when to replace those shoes to stay at your most optimal.
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If you've ever experienced the "runner's high" you're no stranger to the feeling of when adrenaline is pumping and you almost feel weightless as you log your miles. That is…until you get injured. Then running can turn into an activity that you absolutely dread.
While some injuries aren’t preventable (sometimes a sprained ankle or shin splints are inescapable despite your best efforts), you can improve your chances of sidestepping injury with the help of your running shoes.
You may love your shoes and feel like you could run in them for years, but this is often a bad idea. It’s actually extremely important to replace your running shoes frequently. Plus, those worn-out kicks can be the culprit for many injuries. So, when exactly should you be replacing your running shoes?
Ahead, our experts guide you through the significance of timely shoe replacement so that you can run optimally and prevent injury in the process.
Related: The Most Ridiculously Cushioned Running Shoes of 2023, According to Our Tests
Understanding Shoe Degradation
Even if you own the cream of the crop running shoes (we’re looking at you, Nike Vaporfly shoes), unavoidably, your shoes will experience wear and tear over time. This is due to a wide array of factors, including how much mileage you put in regularly, the types of surfaces you run on, your foot strike pattern, and the shoe construction.
Simply put, running shoes are made of materials that break down over time, says April Gatlin, Master Trainer for STRIDE Fitness. While running shoes often offer ample cushioning to absorb shock and provide comfort, that foam will break down over time, which becomes a problem for your biomechanics, explains Scott Socha, pedorthist and ultramarathon trail runner. When you’re not running optimally and your biomechanics are thrown off, this can lead to injury.
“Running shoes with foam midsoles eventually wear down because of the compression of materials in the shoe design,” says Socha. This gradual breakdown of all your running shoe components can eventually reduce not only comfort but also support and shock absorption. “Cushioning can protect against ground reaction forces and aid with general comfort during a run,” says Socha. “When this foam gradually breaks down, if you supinate [roll to the outside edge of your foot during a foot strike], for example, you start to supinate even more than when you are barefoot.”
Supination can put tons of strain on the ligament that connects your heel and toes, which can bring on that all-too-painful condition, plantar fasciitis.
Cushioning is also key when it comes to the impact on one’s joints. “If the cushioning begins to break down, the impact on the body intensifies, making it more severe and possibly causing injury,” explains Gatlin.
As for outsole tread, or the grippy bottom of your shoe, it’s likely the most durable material of your running shoes and normally takes longer to break down. “As it breaks down, it doesn’t have the negative effects on biomechanics that midsole cushion does,” says Socha. All that wear and tear does eventually show up on the outsole, affecting your support and also allowing outside objects, like rocks and roots, to penetrate more easily. “This makes running outside more hazardous,” says Gatlin.
Then there’s upper integrity, or the state of the material that covers your foot. It’s important for your uppers to operate at their best because they keep your feet in place in your shoes. Gatlin cautions, “If the laces or upper integrity of a shoe begin to become worn, the foot can move around, which then can provide instability in the foot and knee joint.” Socha also says that upper integrity is important for fit.
Related: The Ultimate Guide to Running Shoe Terminology: Understand Key Features for Your Best Fit
Signs that Indicate Shoe Replacement
Unfortunately, your running shoes can’t tell you when they need to be replaced—at least not yet. For now, you’ll need to be on the lookout for key signs that a running shoe switch is necessary. This can include things like visible wear and tear, flattened cushioning, loss of tread grip, and discomfort during or after runs.
You're Experiencing Pain
Specifically, if you begin to experience pain and your shoes have foam for cushioning, that’s a big indicator that it’s time to retire them, as Socha says.
The Foam Cushioning is Visibly Broken Down
What’s another way to know that your shoes’ foam is shot? Look at the foam on the bottom inch of the heel for a clear sign. “If the foam is smashed to pieces, then it’s time to replace the shoe,” says Gatlin.
There's Been a Shift in Your Gait, Weight, or Stride
It’s also helpful to pay attention to any changes in your foot alignment, stability, or recurring injuries. These all tend to be potential indicators of worn-out shoes, and the additional wear is “exacerbating your weaknesses,” as Socha puts it.
“Every time there is a strengthening in lower body muscle groups, or a change in weight, or a change in gait or stride (i.e., a person becomes a faster runner), the foot will strike the ground differently. A worn-out shoe is a great indicator of how the person is striking the ground and will help in selecting a better shoe fit for the new pair,” explains Socha.
That’s why when you go to a running store for a foot strike analysis before buying a new pair of shoes, they’ll often ask you to bring your old pair so they can observe the wear and tear and learn more about your habits as a runner.
Mileage-Based Shoe Replacement
You may be familiar with this commonly recommended guideline that often permeates the running world: it’s a good idea to replace running shoes every 300 to 500 miles (or 480 to 800 kilometers). But why? Can’t you just push through to 1,000 miles?
Nope, not really. Our running experts both agree that to prevent injuries and pain caused by midsole breakdown, 300 to 500 miles is the way to go. Keep track of your mileage on your favorite running app, and when you see it inching its way past 300 on its way to 500, it’s time to start researching new running shoes.
In addition to mileage, other factors like running style, body weight, shoe type, and shoe quality can influence shoe lifespan and the need for replacement. Agreeing that these are “all big factors in shoe replacement,” Gatlin notes that in general, the heavier the person, the quicker the cushioning will break down since there is more impact per step. She also says that the type of runner you are can influence how often you need to switch up your shoes. For example, marathon runners put more miles on per week, so they will likely need to invest in new shoes sooner than runners who do 10 to 15 miles per week total.
Time-Based Shoe Replacement
Some runners base their shoe replacement on time, or shoe age, in addition to mileage, since materials can deteriorate over time, even with limited use. The general guideline for a time-based shoe replacement is 6 to 12 months, even if they haven’t reached the typical mileage threshold.
But time isn’t always the best way to assess a shoe replacement. Socha recommends that instead of going by a monthly timeline, go by the actual mileage of the shoes, “since a runner's weekly and monthly mileage will vary depending on the athlete and their training.” He adds that beyond time, many factors go into the wear of a shoe, so it’s important to consider all factors.
While foam can hypothetically lose its full potential with age, as Socha says, he personally hasn’t experienced “stale foam” from not using his shoes.
Some experts do believe you can go according to time. Gatlin says that since the materials will naturally start to disintegrate after a certain amount of time, the shoes will in turn become less supportive. She advises switching out your shoes closer to the 6-month deadline rather than 12 months.
Whether it’s mileage-based or time-based, it’s up to you to ponder your unique running needs and style and decide which approach is best for you.
Individual Factors and Personal Assessment
Individual factors can be significant when it comes to replacing running shoes, from running mechanics to foot anatomy to injury history. Yes, running shoe replacement can be downright scientific at times.
“Running mechanics, foot anatomy, and injury history always need to be examined when purchasing a new shoe,” says Gatlin. “This is also important even if the intent is to buy the same exact shoe as previously worn. If the person has become a faster runner, or the leg strength has increased, their foot strike may be different, which may encourage a different type of shoe.”
This is why it’s essential to assess your shoes regularly and even consider seeking professional advice, such as a gait analysis or consultation with a running specialist for personalized recommendations.
Risks of Wearing Worn-Out Shoes
You may have already gotten the drift: there are quite a few potential risks and consequences of wearing worn-out running shoes, even if it doesn’t seem like a big deal. Your body will definitely notice the difference between old shoes and new, supportive ones.
According to our experts, some of these risks include:
Tendonitis
Stress fractures
Shin splints
Plantar fasciitis
Knee pain
Overall greater impact on the joints
That diminished shock absorption, inadequate support, and compromised stability on running mechanics and overall performance will add up, trust us.
Caring For Running Shoes
We know that running shoes aren’t exactly cheap. That’s why it can be beneficial to try to extend the life of your running shoes. Some of these approaches can include rotating between multiple pairs, properly cleaning and drying your shoes, and storing them in a cool, dry place.
“I rotate a few shoes throughout my weekly runs,” says Socha, adding that he personally prefers shoes without a foam midsole. If this idea appeals to you, a minimalist running shoe could be for you. This isn’t a great idea though if you’re prone to injury or currently dealing with an injury, since minimalist shoes aren’t as cushioned or supportive in some instances.
Gatlin says that some runners will have two pairs of running shoes and alternate between them each time they go for their run. “This will double their lifespan,” she says.
Additionally, generally maintaining good foot hygiene (wearing high-quality socks, keeping your toenails short) and regularly replacing insoles or inserts can increase optimal shoe performance.
“Insoles and running shoes are synonymous,” Gatlin says. “When one is replaced, it’s a best practice to replace the other so materials do not break down, causing pain or injury.”
So, to wrap up: running in very old shoes is bad. Replacing them every 300 to 500 miles is good, for your running performance and for injury prevention. Keep an eye out for any wear or tear, from the outsoles to the foam to the uppers. While you may track mileage and complete training plans, you need to pay attention to your shoes so you can always run at your best. Simply, prioritize your foot health and invest in high-quality running shoes for a comfortable and injury-free running experience. Your body will thank you for it.
Related: The Best Insoles, According to Podiatrists and Customer Reviews
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