Anyone actually had SPD cleats get worn out by walking on? The edges of the cleat that engage the pedal are more recessed than the face of the cleat, so they don't seem to get any direct wear while walking.

Mine are fairly well scratched on the bottom, but they still work fine. They're wearing out faster from all the clipping/unclipping I do than from being walked on. I've used 'em I guess maybe a year now?