听听专门治疗足部损伤的医生是怎么说的。
http://tanglewoodfootspecialists.blogspot.com/2009/02/when-to-replace-running-shoes.html

“We all know that running shoes do not last forever. Most people, however, continue to wear them well after their useful life has ended. Most commonly in my office I'll have people tell me that their shoes are three years old BUT (insert excuse here...). Some of my favorites, it fits my feet perfectly (meaning it's broken down), the heel is worn out just how I like it (meaning it has a hole inside the shoe), new shoes just bother me (meaning that I've worn these for so long, the support is too different at this point), and my favorite: They still look new.”

“The support and function of a running shoe has little or nothing to do with the overall appearance of the upper part of the shoe or even the sole. It's the midsole, the portion of the sole that is largely invisible from the outside, that has the most function and limits the useful lifetime of a shoe. With every stride, the midsole compresses and, with time, loses the majority of its support.”

幸亏你不跑步，不然Dr. Andrew Schneider又要多一个病人了。。。