First off. Oh. My. Goodness. These are amazing, I mean AH-MAY-ZING boots.
If you have a calf size of 15" or under, then these should fit (I take an 11 and these are what mine measure).
However, I have a muscular (I call it muscular, but, in truth, it's just fat) calf. 18"
I decided to order these boot because I just absolutely fell in love with them from the photos. Quite the investment, but Amazon is so good with returns, I thought it worth the risk.
When they arrived, I just knew I had to figure out a way to get the calf stretch so I could wear them (without stretching, I could not even get these on).
I called my local shoe repair and lucked in to one who had those old-style metal calf stretcher. EUREKA!
After 5 days on the stretcher, I'm pleased to say they were able to stretch them to 17".
I still can't pull them up completely, but I can get them on with a boot horn and they look awesome a little slouched.
I'm hoping that, with time, they will stretch some more. (I do have them on over leggings and tall socks and am wearing them in the house right now to help keep the stretch going - I just got them back today, so I am loving them up while they're still new - LOL).
Bottom Line: Amazing quality boot made in Mexico; True to size, maybe a smidge big...in my case, with taking an 11, I do think a 10.5 would be too snug. I also think I'd be able to wear a sport sock in these; The look is beyond believable.; The vintage feel/look is awesome; The calf is maximum 15" around.

I wish Frye would make more extended calf boots. If I didn't already own the Veronica Shorties, I'd invest in the extended calf Veronica talls, but, I do think there are at least 3 or 4 others I'd be tempted in if they had extended calf.

4 out of 5 simply for the calf size. Otherwise, this is a 5 start boot. Heck, it's a 100 start boot.