When I worked overseas inside a number of footwear factories doing production management, several of my coworkers were avid runners. They would request that the factory would put a "shot" of liquid EVA intended for a Size 9 into the mold for a Size 11 (for example). That meant that the resulting midsole was much softer than spec. They'd get about 50 miles out of a pair, but they all loved the cushioning. They'd have the factory produce a half-dozen at a time.Me... I burn through running shoes. About a half dozen or so per year.