My husband went to an expensive running store to get fitted for shoes and these were what was recommended. They cost much less through Amazon than in the stores. He has been buying this same model for a couple of years and they really help him. Prior to finding these, he had terrible pains in his knees when ran. These do the trick and he knows when he needs a new pair because his knees start hurting again. They seem to last him about nine months and he runs about 3 times a week.