A remarkably large number of skaters live with the consequences of ill fitting skate boots.
Even some of the world's top skaters, using boots custom made for them by the best,
suffer injuries. In addition, their boots and blades do not last as long as they should,
and may have problems performing as well as they should because of these issues.
I believe that most people can modify their boots to fix most of these problems. The high cost of skates makes this highly desirable.
I claim:
Caution I am not a certified expert. This treatise is based on my own and other's experience, together with the basic principles of physics, chemistry and biology. Boot fitting is more art than science. People use variant techniques to fit and modify boots. People vary substantially in sensitivity to boot fitting problems and to the chemicals contained in the leather, in the amount and composition of sweat, skating styles and disciplines, the amount of reinforcement and motion they expect from their boots on various parts of their feet, the frequency with which they skate, and the weather and climate in which their boots are stored. There are very knowledgeable people who disagree with anything and everything I say here.
Further, skating boots, especially figure skating boots (because you will switch between balancing on the inside and outside of the foot), need to fit more tightly than would be considered healthy in normal footwear, to achieve better blade control. But an optimal 3 dimensional fit doesn't need to be quite as tight, because you aren't using excessive pressure to deform the boots to fit your feet.