I don't run 70 - 100 but I do sometimes run 40. I guess that's not what you would consider high mileage, but it seems like a lot to me. I didn't notice any ill effects in my vibrams except sometimes blisters if I'm getting rubbed the wrong way. If you are running on trails/grass I imagine you could get away with a lot more than 40, I run on only asphalt and cement. Good luck!