The gasket, the windshield, and the car body are bound together with a special adhesive. This strong adhesive allows the windshield to stay in place and also creates an air and water-tight seal. Even if a automobile windshield chip repair is not cracked, it is sometimes necessary to replace the gasket because they can rot and deteriorate over time.

Good question. Windshield crack repair equipment varies widely among companies. High quality resins, injections and air removal methods vary from company to company and can affect the finished repair. Quality injection units and high quality resins are as important as the technicians performing the crack repairs. The quality resins create stronger bonds and resist yellowing better than inexpensive resins. Quality injection equipment will remove more air and the injection capabilities provide a higher quality crack repair.
If you do decide that fix auto glass is your best bet, you have a few choices. First of all, make sure you check to see if your insurance covers it. In a lot of instances it does. The problem is that many policies have a deductible that is higher than the cost of the replacement or repair job. If that is the case, you will have to pay for it yourself.
If you have insurance that will cover windshield repair with a low deductible, this may be a good option. Many companies that specialize in windshield repair will pay the deductible for you provided it's under $100. If you call ahead to make an appointment most of these companies can replace the windshield in less than an hour. If you don't make an appointment, you may have to wait a few hours if there are many customers in front of you.
Jolt your car or windows. Try to avoid slamming doors or shutting doors with the windows all the way up. Creating extra pressure inside the vehicle in this way can cause the crack to spread.
Not all chips and cracks can be repaired when windshield damage occurs. It is definitely worth the time to have any damage evaluated by a professional to avoid further cracking and damage and eventual replacement.