Do not replace your running shoes after 600-800 km as a matter of principle; as long as they are not physically deformed and you do not feel any discomfort or pain, they remain usable, potentially up to more than 1500-2000 km.

noli's read

The idea that shoes must be replaced at a fixed distance is widely pushed by marketing, whereas scientific research (notably observational studies on material wear and biomechanics) shows that the degradation of cushioning is progressive and varies according to the runner. A study published in the 'American Journal of Sports Medicine' suggests that while cushioning decreases over time, this does not necessarily increase the risk of injury for all runners, because the body adapts. However, it is true that modern foams (often made of PEBA or advanced EVA) retain their energy return longer than older generations, partially validating the idea of an increased lifespan. The exaggeration lies in the idea of pushing to 2500 km: although the foam is still there, the structural integrity of the upper and the outsole is often compromised, which can subtly alter the gait without the runner realizing it immediately. It is therefore wise to prioritize how your body feels, as suggested, while remaining vigilant about the asymmetrical wear of the sole, which can force joint compensations.

the sources

No named source held this one up — that absence is part of the verdict.