Michele, I don't put in the mileage in a year that you do in a month, but thought I'd share my recent shoe buying experience, just because (1) I have long toes, which means that most shoes that fit me per a size measurement and don't cramp my toes, also are way too big for my actual feet; and (2) I was in NB 766s.
I'm now in Mizuno Wave Inspire 4 in Wide, a size and a half bigger than my old Regular width NB 766s. My heels don't slip, my arches are supported, my toes aren't cramped, my toenails aren't getting pressure, the big callus on the outside of the ball of my foot isn't getting aggravated. At age 49 it's a total revelation to me that shoes can fit this well.
I'd tried Mizunos years ago... these fit way differently. I tried out the Wave Rider 11 also and they were an equally good fit, just not supportive enough for me. So. Might be something to try if you haven't given the larger sizes a chance. Warning though, the Inspires are breaking down VERY quickly, and I'm not that heavy - I've read that complaint about them on 'net reviews, so it's not just me.
My own running.... well, I'm still slacking off
After Indian Summer last week and four good-length rides in 70 degree sunshine, we now have highs in the low 40s, cloudy and miserable. I'm giving myself the week to mope, work out indoors, generally get my head around the idea of cold. Next week I'll crack the running whip!
Speed comes from what you put behind you. - Judi Ketteler