Ski Boots

Hi to all those pining for the return of snow. In the mean time I have a
question about ski boots

My son skied in a pair of Salomon Ski boots for a 12 week stint this winter
(instructor's course in Fernie) and although the boots are rather scuffed
seemed to be in an okay condition. Unfortunately one of the boots has
cracked at the swivel at the ankle and the manufacturers say that it was a
fault in manufacturing and have refunded some of his money! For some reason
they seemed unwilling to simply supply a new shell (?) so I was wondering
whether anyone knew where we could buy a single shell for a Salomon boot?
Also is it worth it, do boots have a use lifetime beyond which they should
be thrown away - it seems to me that most people develop their skiing and
move up the range or boots age over several 1/2 week per year seasons so are
replaced.

Cheers

Paul Schofield