My definition: the skate is broken down if it no longer provides adequate lateral support, or if it bends in such a way as to impinge painfully on some part of your foot.
By lateral, I mean the inside (med-speak: medial) and outside (med-speak: lateral) part of your foot.
Bending and impinging can also include the toe box, especially if you jump.
It would be easy to photograph your boot(s), and email it and the question to the boot maker. Describe what you feel that makes you unhappy with the boots as they are. They know best what they are willing to do, and for how much.