As runners, saying goodbye to our favorite pair of shoes that served us so well can be one of the hardest things to do. Of course, we all know those runners who look for the slightest excuse of wear-and-tear or blemishes to justify a new pair (and when there are so many new, great looking models out there, the temptation to trade-up is very real). On the flipside, we’ve all seen pairs out there on the track that look like they’ve been worn for decades, showing often more holes than shoe.

Why replace running shoes at all?

If looks don’t matter to you, then it may be hard to justify replacing your running shoes when the pair you currently use work “just fine” - despite maybe some damage and wear-down. The truth as to how often should you change running shoes lies beneath the surface of the shoe itself. After a certain amount of use, the integrity of the shoe may be affected and that leads to the real reason to replace running shoes: increased risk of injury. Put simply, the longer you run in shoes that may not have the components and structure they were designed with, the greater your risk for damaging your body.

Just like driving a car on bald tires: you could keep going, but the chance of something bad happening increases each time you hit the road.

So how long should running shoes last?

Estimations on how long running shoes should last vary, but as a guide, in the right conditions shoes should last between 500 and 750km (310 and 465miles) before they are compromized. Obviously if you’re a seasoned runner or professional that heads out on a long run each day, then this can mean you’re in need of a new pair of shoes much more frequently than someone who runs for fun or casually. Every shoe and runner is different, so below we’ve highlighted the major things that can affect the lifecycle of a running shoe, and signs to look out for when deciding if it’s time to say goodbye to your trusty run companion.

What affects the life of running shoes?

When it comes to determining how long running shoes should last, three main factors need to be considered to help you determine their lifespan.

1. Run terrain

Where you run; on the road, trail, track, inside or a mix, is one of the biggest factors that will determine how long your pair of running shoes lasts. Most running shoes tell you what the ideal terrain for that pair is, and for those that don’t, road running is usually standard. In reality, most runners have some cross over with where they run – even the city has rocky and dirt-covered parks that vary the kind of environment the sole of your shoes are exposed to. The main thing is making sure that the majority of runs you do match the terrain the shoe was made for, or else that shoe may not be the best choice for a long life of use. 

2. Run style

The kind of foot strike you have also plays in to the life of a running shoe. If you are unsure of your impact zone when you run, take a look at the bottom of a well-used pair of your running shoes and see what part has the most wear: front, middle or heel. Knowing this arms you with more information when it comes to looking for a better suited running shoe, and choosing one built to sustain your style.

• Forefoot striker: the most common kind of foot strike for sprinters and hill runners, your shoe often wear under the big toe or off to the outside/side of the shoe’s front. Often the outer-sole becomes broken through to expose the midsole or in extreme cases, the sock and foot.
• Midfoot: the area under the ball of the foot (middle of the foot) that wears through in much the same way as the forefoot.
• Heel striker: common run style for longer distance road runners. Unfortunately, statistics show you are most often in need of replacing your running shoes compared to the other two types. Although the rest of the shoe may look pristine, if the heel of the shoe is worn down excessively the foot and ankle may be compromised providing a gradual decrease of support, which can lead to injury before you know it.

Remember, there is no “right” style necessarily when it comes to where your impact zone lies. Understanding and knowing which kind of runner you are is simply the first step (quite literally) in being able to better find the right shoe for you.

3. Runner’s build

From those factors that affect the shoe from the bottom up, to the main one affecting it from above: you. Who you are: your weight and height especially, plays a key role in knowing how long a good pair of running shoes should last. Most running shoes take in to account the “average” runner for their shoes in terms of what data is available in their market. From this, a runner profile is created and shoes built to accommodate this type of average person. Being heavier than this profile means that often a shoe may wear down quickly, and being lighter might mean the shoes last far longer than average. The same can be said about taller vs shorter runners. If your build varies greatly from the “average” there are some shoes that may be best suited for you. Chief amongst these are the ones with increased support, as often these are reinforced and made to be more forgiving on certain kinds of wear. If unsure, the best thing to do is ask before you purchase if the shoe will work for your build to make sure that it lasts as long as possible.

How to know the life of your shoe is coming to an end: common signs

On the sole

The most obvious sign of when to replace running shoes is the sole. Wearing down the tread until it is smooth and the overall change in the base-sole-shape of the shoe is one of the clearest indicators that it might be time for a replacement. This can be tricky as some parts will show much greater wear compared to other parts of the shoe (depending on what kind of runner you are). Luckily for On fans, the bottom of the soles through the patented CloudTec shows you clearly when an element is done by breaking through. When this happens, the shoe is beginning to be compromised and it’s time to start thinking about a new pair.  

The upper wearing down

If the sides of your shoes have worn through but the sole of it still is in good health, it could mean that you’ve chosen the wrong size for your foot. Though length is how shoe size is measured, wider or “flat” feet can quickly wear through the sides of running shoes. If this is happening to you, a half-size larger could be what’s needed for your shoe, or stretch laces that can adapt to the foot on the run (such as you find on the Cloud ). If you’re still burning through the sides of your running shoes, a reinforced upper may also be something to consider.

Fraying of the inside heel

Like with wearing of the upper, early breakdown of a heel can be from a sizing mismatch and the ankle coming out and causing friction on the run. A simple fix for this can be retying the shoe’s laces to provide greater support up the top of the foot, preventing the heel and ankle from escaping the shoe. As well as that, lower-cut socks can also wear-down the inside cushioning and material before their time, so consider higher-length socks if you start to notice the back of the shoe coming undone.

More than meets the eye

Of course, even if the upper of the shoe looks new, and the grip on the bottom still has tread, the internals of the shoe may begin to be compromised out of eye-sight. A telltale sign of most running shoes is the springiness of the sole, especially on “everyday” trainers. Over time, the material of the sole can harden from natural conditions (such as from running in the wet) and lose much of the springiness that helps cushion footfalls and protect knees. A gut feel is needed to an extent here: if you poke and squeeze the sole and find it solid when once it was springy, this could be a sign the material has hardened and aged and may need replacing.

Pain and injury

Aside from all the other signs, the most important one to be on the lookout for is pain. A great pair of running shoes should leave your body feeling as good as when you began, with no lasting pain points. If you find you’re beginning to experience soreness in places you had none before – especially in the feet, shins and upper back, it could mean the shoes are in need of replacement. Listening to your body is the best way to judge when to replace running shoes and to prevent injury before it’s too late. 

If unsure, ask

Just like when you head to the mechanic, there’s nothing wrong with asking your running expert or local shoe store for their opinion on how long your current pair might have left in them. By having your current shoes on hand it will make it easier for them and you to see where exactly the wear and tear has happened and to make sure the next pair of running shoes you choose addresses any damage that may have happened before their due time.

On offers a free service where you can contact the Happiness Delivery team with pictures of your current shoes and get feedback about if they need replacing or not – you can find out more about this service here.

Lengthening lifespans

Shoes are an investment in preventing injury and promoting healthy living. They can also be expensive, especially when training for a big event and wearing through various pairs in a short period of time, which is why there are a few things you can do to prolong the life of your running shoes.

• Dry them after use – of course shoes get wet, both from the inside and out, however drying them soon after use can keep them in action for longer. Moisture often seeps in to the glues and material of shoes, weakening them over time, so keeping them dry makes them last longer.
• Rotate between two (or more) pairs of shoes – this allows for shoes to “recover” from you, and also helps you from being overly conditioned from the way one pair of shoes or another may have you running and changing your run-style over time.
• Undo the laces before sliding on and off – stepping and crumpling in to a pair of running shoes damages the structure of the shoe, especially the heel, over time. By undoing the laces and being seated when you put your shoes on, they remain strong and intact - unless of course they have speed laces made for you to slide in to (such as the Cloud).
• Wear the right socks – shoes are made to protect from the outside in, so make sure the quality and condition of your socks (if not running barefoot) matches those of the shoes themselves.

Gone but not forgotten

Thanks to some great running apps such as Strava, you can record what shoe you are using on your runs. This serves the dual purpose of being able to look back and know just what pair it was you had on when you beat that PB or ran in a certain race, as well as tracking better just how far you have run on the shoes. Finding out just how far you may have come on your current running pair of shoes may surprise you, so apps come in very handy - especially when you start a new challenge such as, for example, running 1000km in a month for the very first time (and staying injury free)...