Barefoot Running

[KnottedYet]

now that I'm satisfied that the whole mileage-limit-replacement thing is basically a scam.

Did you see this research paper? http://www.ncbi.nlm.nih.gov/pubmed/18801775

From a cushion standpoint, there is no need to replace shoes as the cushioning loses its sproinginess. (this is related to those "turkeys running on treadmills" to study leg stiffness: the body adjusts to get its optimal suspension) However, from a distortion standpoint it is very important to replace shoes if they become distorted from wear to the point they are interfering with posture or efficiency. (the heel that is almost completely worn off on the outside, the ripped lateral fabric, the pulled lace-holes, the burst gel bladder, etc.)

Side note: my favorite running sandals are now more than 10 years old, and I just did a half marathon in them this weekend. They have not distorted, and they were never crazy cushiony to begin with so there hasn't been a real loss of sproinginess. (they never had it) No-one can convince me that I need to replace them, and I won't until I feel they have distorted and are messing with my efficiency. I did get them resoled because I wore the old sole off. My second-favorite running sandals are a different style and only 8 years old and unfortunately do have to be replaced (I just ordered new ones). They got a little funky in the process of being worked on and resoled, and I just can't run comfortably in them now.