When to replace running shoes: a plain-English guide

Watch the shoe, not the calendar

Running shoes don't have a best-before date. The part that matters most is the midsole — the layer of foam between your foot and the outsole (the bottom of the shoe). It compresses and loses bounce gradually. The outsole wears down, the upper (the fabric part) stretches, and the heel collar can soften. How fast this happens depends on your body weight, the surfaces you run on, the weather, how you store them and whether you rotate pairs. There is no universal kilometre count that applies to everyone.

You may see a mileage rule quoted by shoe makers or running shops. Treat it as a prompt to check your shoes, not a rule. It also helps to notice how they feel on easy runs, when you're not chasing pace.

Signs it's time to replace them

Look and feel, together. One worn patch isn't automatically the end, but several small signs usually mean the shoe is tired.

• The cushioning feels flat or dead, especially under the forefoot. You feel small stones sharply through the sole, or the shoe no longer feels springy when you press the midsole.
• The tread is worn smooth in the areas where you land and push off, or there are holes in the outsole.
• The upper is torn, the heel collar has collapsed, or the laces and eyelets are failing.
• You're getting new rubbing or blisters in the same place, without changing socks or distance.
• Your legs feel more beaten up after easy runs than usual, or a pair feels noticeably harsher than your newer shoes on back-to-back runs.

Pain is a separate signal. If pain changes how you run or keeps coming back, see a GP or physio. Shoes can be part of the picture, but they are not a diagnosis.

What about mileage?

Some runners replace shoes after a set distance. It's a useful nudge if you like a reminder, but it ignores too much: your weight, your stride, the surface, how often you wear them for walking, and the type of foam. Use the number as a checkpoint, not a deadline.

Carbon-plated racing shoes (stiff plate plus springy foam) are a special case. They return more energy and are designed for racing, but their foam breaks down relatively quickly. Save them for races and a few key sessions, and race-test them two or three times before the big day. For most training, comfortable, cushioned daily trainers are exactly right.

How to make a pair last longer

• Alternate between two pairs if you can. It varies the load on your legs and gives foam time to recover between runs.
• Air-dry them at room temperature. Stuff them with newspaper if they're wet, and keep them away from radiators, tumble dryers and hot car boots.
• Untie the laces before putting them on. Forcing your foot in stretches the heel collar.
• Use running shoes for running. Walking all day in them adds wear without adding training.

A fresh pair won't fix a training problem on its own. If you're increasing distance, keep most runs easy and build in rest. Strength training for hips, glutes and calves is often more useful than shopping. If you're just starting, how to start running for beginners covers the first month without jargon.

When to see someone

If you have pain that changes how you run, chest pain, dizziness, or anything persistent, see a GP or physio. Don't try to run through it or self-diagnose. New shoes are not a treatment.