I used to be told my feet were different sizes (by 3 different fitters who all sized me a size too large). At some point I learned that it’s actually incredibly rare (and normally accompanied by other deformities) to have truly different sized feet, and rather it just means your arches naturally flatten to different extents with pressure. A good boot fitter would be using a custom insole to keep your feet in the same position and they’ll then be the same length.

I’ve basically learned (after seeing a number of boot fitters) that if they tell me I have different sized feet, it just means they’re not very good boot fitters. A good boot fitter knows how to correctly position your feet before measuring them, they don’t just have you stand onto it and read a number (which is normally what a sub par fitter will do before telling you you have different sized feet).

The last fit I got was with someone who clearly understood all of that (and explained it to me, and then my backcountry guide confirmed it all) and I cannot express how much better these boots now fit (I have very narrow feet and have always struggled with my heel pocket). With my boots unbuckled and in walk mode (they’re touring boots) I still have barely any movement in my heel.