How Long Do Running Shoes Last?
How long do running shoes last?
It is an age-old question. We hear it every day. The answer typically provided by shoe retailers and manufacturers alike has been of the one-size-fits-all variety: “a typical running shoe should last 300-500 miles”. Zzzzzzzzzz. That is not particularly insightful. Primarily because that mileage range is so wide you could taxi a Dreamliner through it. Let us leave the one-size fits all approach to terrible wedding tuxedo rental centers.
People are confused. Therefore, we have taken a different approach at the Brooklyn Running Company. This approach is not complicated. There is no smoke. And there are no mirrors (other than the one you use to confirm your foot looks fabulous.) Our approach is tailored to each individual and is integrated into our footwear fitting process. It all starts with a good conversation…and a footwear expiry sticker!
If someone tells you your shoe should last about 300-500 miles, well, that’s kinda lazy. And frankly, not helpful at all. We have started to employ a footwear expiry sticker as part of our fitting process. We place it under the insole of your shoe as a reminder of 1) when you bought it, 2) a suggested “check-up” date, and 3) our best estimation based upon our conversation as to when your shoe will expire. Our experience with most individuals is that their running shoe will “expire” every 3-6 months. The specific expiry date chosen will depend upon what was learned in our conversation and will be based upon the aforementioned influencing factors.
So how long DO shoes last anyway?
There are several layers to this question that must be addressed, so let’s dive into the weeds for a brief moment. We will break it down for you in a few different sections, beginning with a brief discussion on shoe “foam” (i.e. base level cushioning) and the effect its degradation has on a shoe’s lifespan.
Shoe “foam”, for decades consisting mostly of EVA (ethylene-vinyl acetate), is a polymer used to absorb physical impact. (Holla, Wikipedia!) Sparing you too much science, EVA breaks down over time as it is susceptible to compressive forces when running, walking, etc, which degrade the resilience of a shoe’s cushioning. Aside from the repetitive forces of running on footwear and its foam cushioning, other factors play into a shoe’s lifespan. These factors also affect the wearability and fit/feel of the cushioning underfoot and they include:
Types of Foam and Midsole Materials
In recent years, there have been advancements in the type of materials shoe manufacturers have been using to construct their shoes’ midsoles. The cushioning of traditional midsole materials degrade -in part- due to the slow release of air particles from the foam as your foot strikes compress them. Over time, the cushioning loses its resilience and gets flat and unresponsive. This happens slowly, so most runners aren’t even aware of it until after their legs get a little achy. As discussed, shoe companies have typically used a foam blend known as EVA (or some variation of it) that has become standard throughout the footwear industry. EVA has proven to be a sufficient shock absorbing material for running shoes, being forgiving enough on impact but still having enough substance to help spring your weight forward on toe-off.
However, some footwear brands have recently come out with new shoe technologies. Benefits include the mitigation or delay of this breakdown process. Adidas is one example, and they now incorporate a midsole material called “TPU” or “Boost” in most of their running shoes. This material consists of thermal plastic units fused together to create the Boost midsole. TPU material does not contain air molecules and therefore, Adidas’ argument is that their Boost shoes are able to maintain shape (and thus your shoe’s overall durability) for longer periods of time.
Other brands such as Brooks, New Balance, Nike and Saucony have all come out with their own proprietary take on the best midsole cushioning materials. Each has its unique pros and cons for the discerning consumer. Whether you use a TPU based midsole, or an adaptation of EVA, there are other factors that will affect your shoe’s lifespan. These can be of notable importance depending upon where you live, how you live, how you run and how you store your shoes.
Believe it or not, temperature and/or climate (including the variability of it) affect the lifespan of your footwear in a number of ways. In colder temperatures, where there is less moisture in the air, your shoe actually firms up under-foot, creating a slightly stiffer shoe sole and ride (on the run). It’s not just your muscles that are cranky on cold days! If your shoes are stored outside or near a less-insulated area of your house or apartment, this may actually cause the shoe’s midsole cushioning to feel firmer than it would under a more temperate setting.
On the contrary, temperatures above the norm (anywhere above 80 degrees) may cause the cushioning elements of your shoe to soften up, again affecting both the ride and the feel underfoot. Footwear lifespan can be compromised considerably in extreme temperature/climate conditions and large swings in it. Those in the Northeast face this challenge because outdoor temps can swing by more than 100 degrees within the same calendar year!
Can an unworn shoe, just sitting on a shelf or in a closet, expire like milk? In short, yes. It just takes a little longer. (FYI: this should concern those in the habit of buying older models of their favorite shoes online.) But unworn shoes are not expiring for the reasons we thought. We’ve always wondered about the concept of shelf life, mainly because we don’t want to be selling footwear that has degraded simply by overstaying its welcome on our stock room’s back shelves (not every single person loves our tastes in color). So we reached out to our beloved footwear brands, those who design and make these shoes, each of whom then worked with us to understand what the “at rest” average shelf life is for your unworn shoe.
Their answers were consistent. Generally speaking, the process of midsole cushioning degradation, excluding that caused by impact force, takes up to 5 years before one is able to detect any noticeable difference. That’s good! However, what was interesting to discover is that the glues holding all of the different pieces of the shoe together are what break down first. And there are reportedly large differences between the quality of glues used by the brands, resulting in some shoes breaking down faster than others do. So your midsole will be fine, but the rest of the shoe will have fallen apart. Eeek.
There are a multitude of factors that influence the useful life of your running shoe:
- Running mileage
- Other uses (gym, walking to work or around the neighborhood, wearing it to the bar, etc)
- The brand and even individual model itself
- Body type (someone who is heavier will break down the same shoe relatively faster; sorry, it’s true)
- Gait and footstrike
- Climate (rest assured, we house our puppies at a comfortable 70-72 degrees all year long)
Brooklyn Running Company