I have many pairs of Hotter shoes, some quite old and still in good condition, but I have also experienced rapidly crumbling soles when the black material turns to dust or breaks off in chunks. The latest experience was yesterday in a pair that I had worn only once before. They felt sticky at first, then left a trail of black "crumbs" and finally large pieces - all within the space of minutes. Admittedly they had been stored on a shoe rack for months but with plenty of air circulation. (A friend who had a similar problem was told it was because she kept them in their original box. Please Hotter change the composition of the soles you use because in all other respects you make a good product and you are losing formerly loyal customers. I know I shall be very hesitant to buy further pairs.