The kyBoot sole stays supple even after intensive use. Depending on the surface and body weight, the sole is designed to last roughly four million steps. You will only notice that the sole becomes somewhat softer over time. That does not mean the quality is impaired; the kyBoot sole is just more sensitive than that of a normal shoe.
A body weight of over 100 kg/220lbs may reduce the kyBoot‘s lifetime by roughly 10% per 10kg above 100kg.