I always go to the bigger size if my size is right at the end for this reason... In my experience, if your size is on the edge of being barely small enough for the binding, you run a big chance of the binding not fitting if you ever switch boots, or if you are wearing a brand of boot that is not the same brand as the binding. My second reason is that in my experience, it is an absolute pain in the ass to get the binding to fit if your foot size is right on the edge of being to small. You have to widen out all of the straps and get it configured just right for what may still be to tight of a fit. The bigger binding is going to give you room to grow (if applicable), versatility when it comes to boots, and a probably a better out of box fit to your foot size.