Our state typically has a $50 - $100 deductable on auto glass replacement. Most of the auto glass companies take advantage of this and offer to pay your deductable for you.

After one particularly hot summer day - I returned to my parked car after a day at work and found my rear window completely shattered into bazillions of tiny pieces. Needless to say - that had to be replaced. Didn't cost me a dime. I didn't find any foreign object to explain it so I can assume then that the heat was at least part of the issue. If a passing car threw up a small stone coupled with the pressure build up in the car - that would explain my experience.

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Spock Jenkins of the Vulcan Jenkins'.