I am a asics fan, and when one pair wears out, I just get anouther and have never had any sizing issues. This pair seems to run a little smaller than my others that I bought less than 6 months ago. Not so small that I had to return them- but small enough that they felt tight for my weeks wear. If you wear asics and the size you normally wear runs just right- you might want to move up a half size. The support in the forefoot is also a little larger than on previous shoes. It takes a little while to get used to, and caused me to have some achille's issues when I wear them for long workouts. I will continue to purchase asics- but this is my least favorite pair.