Here is an uncomfortable figure to start with.

A systematic review of the literature on footwear fitting found that between 63% and 72% of participants were wearing shoes that did not accommodate either the width or the length dimensions of their feet.

Not shoes they disliked. Not shoes that were merely uncomfortable. Shoes that physically did not match the feet inside them.

The same review found that incorrect fitting was associated with foot pain and with foot disorders including lesser toe deformity, corns and calluses. In certain groups the width problem was worse still — with somewhere between 46% and 81% wearing footwear that was too narrow.