The Windshield cracked on it's own under heat on a cold day. I was driving to class with my heat blasting and as I got on the entrance ramp to a interstate, my windshield cracked along the defroster vents at the bottom of the windshield. There was no debris or other facts, or previous cracks, it just gave on its own. Had it replaced my Safelite for around $300. Insurance will sometimes also cover it if you have the proper coverage.