I bought the $300 kit that won Project Farm's head-head on them. For my first attempt I did pretty well. The drill wandered a touch, but end result it almost completely eliminated the spiderweb cracks and a month later, no spreading. Figured it was 1/10th the price of the windshield and I could do worse than needing a new windshield anyway. Now I can repair 49 more hits before I need a refill.