Generally this is a choice only if you act quickly upon getting a stone chip or small crack in your windshield. Over time and with temperature changes, small stone chips and cracks in your windshield often spread into a larger crack. Turning on your warm defroster on a very cold day is one of the most common ways to cause a crack or chip to spread.
Glass companies are quite good at filling many cracks and stone chips in your windshield and it can even save you money. Most often, insurance companies will waive your deductible for a class claim if you simply have it repaired (filled) in lieu of replacing the entire windshield. For most people this can be a $100 to $250 savings. The rationale here is that you are saving the insurance company money, even when they waive the deductible, so it only makes sense that you have a financial incentive to do this.
I've been told that when filling a stone chip that the best results occur when you tend to this repair quickly - before contaminants enter the crack or chip. Some glass shops report successfully repairing cracks up to the size of a dollar bill. Ultimately you should seek the counsel of the automotive glass company that you select to determine if a repair is possible. Generally a good glass shop will employ well trained and certified individuals who can help you with this decision.
If you are having your entire windshield replaced, be sure to ask how long you should wait before you can safely operate your car. In today's car designs, windshields play an important safety role in protecting the occupants of your vehicle and the adhesives used need ample time to cure, which varies with the temperature that they are exposed to.
Lastly, it is important that your windshield provide you with good visibility, without the distraction of damage, and that it is properly adhered to your vehicle per the manufacturers specifications.
These explanations are intended to provide a simple understanding of some of the basic provisions found in most insurance policies. Sometimes simple explanations do not address all of the particular circumstances of a claim, nor may they take into consideration case law or other provisions within a policy. This FAQ section of the website does not replace, alter or amend any language in your policy, its terms, conditions or exclusions.