Hants
Hard Core 4+
I've been told that the big-name insurers won't cover glass crack issues (I know State Farm doesn't).
What I've been told is they will replace it (subject to deductible) if it's "broken" or "unrepairable". Chips, small-ish cracks are generally considered repairable.
IIRC, 18" is the guideline for repairable cracks, but don't quote me on that.