I had a devastating knee injury in 2001. This incidentally was what it took to finally push me off straight skis and those hot pink Salomon Equipe mid entry boots.
Not sure I would ever be able to ski anything off groom again, in 2002 I purchased new gear. For boots, I went with a 45 flex beginner boot for $99 at Gart Brothers.
I was aiming for a comfort fit I now know that I CANNOT ski boots off the shelf. I have a high instep, wide feet, and am very overcanted off the shelf where I need to ski with weight on the outside of my foot to get a flat ski.
Anyways, I was shopping on price for ski boots. Terrible idea. The $99 boots didn't fit my foot at all, but instead of pricing up (and going to a bootfitter) I just kept sizing up until I could get them on my feet.
By the time I could fit my wide feet and my instep, the result was a boot 4 sizes too large. A shell fit showed I had about 2" behind my heel. The low instep of the boot still made for an enormous PITA getting them on and off, so bad that two separate bootfitters gave me their cards when they witnessed me contorting my foot in the lodge to get the boot on.
Trying to ski in those boots was hugely painful. I would curl up my toes to keep the loose heel in place, and skiing on the outside of my foot coupled with toe curl meant CRAMPS. LOTS AND LOTS OF CRAMPS. I wasted a season and a half trying to ski those. I remember lying on the side of Spar Gulch on Aspen in agony with double foot cramps, frantically clawing at both boots to get them off. 10 minutes in socks on the side of a run sucks- and they were cramping again by the time I got to the bottom. Many ski days wrecked not by a bum knee, but terrible boots.
When I actually went to a bootfitter, he told me he had never seen somebody so poorly fit. Getting into a better fitting boot was huge, but the overcant, and some degree of pain remained until this year when I got vacuum boots. Now I can be in my boots bell to bell with no pain, and it is amazing.