This one is right up there with the other famous questions like “Chicken or the egg?” “Paper or plastic?” “Ginger or Mary Ann?” There’s no question that a cracked windshield is unsafe, and it’s not legal to drive with one in many states. Once upon a time, even a small chip meant automatic windshield replacement. Today, windshield repair technology has become a viable alternative, but it still may not be the right fix. Any windshield damage significantly weakens the protective structure of the glass and can be dangerous to you and your passengers.

What Type of Windshield Cracks Can Be Repaired?

The potential for repairing a chipped or cracked windshield depends on the location of the crack, its size, depth, type, age and the severity of the damage. Types of cracks include bull’s-eye cracks, straight or linear cracks, dings, chips, pits and the dreaded star. These types can be repaired successfully, depending on where they are located. Windshield repairs are done by first removing the air from the crack or chip, then filling it with a clear, adhesive resin product. UV light is used to cure the resin. In many cases, the strength of the windshield is largely restored. The repair remains visible, but in some cases, it simply does not hold.

When Should I Replace My Windshield?

If your windshield is damaged in the driver’s line of sight or around the edges, it must be replaced. Generally, if the crack does not fit under a dollar bill, it cannot be repaired. If the damage is on the inside of the windshield, if it has penetrated both layers of glass, or if the safety laminate between the layers is compromised, it must be replaced. If the crack is contaminated—rain has penetrated it, for example—or it’s old enough to have become discolored, it cannot be repaired. If the crack extends over any sensors or the antenna, or if it’s complex, the windshield will have to be replaced. The final decision on whether windshield damage can be repaired rests in the hands of a qualified technician. If the tech does not feel confident that the damage can be fixed safely, you will need a full replacement.

Finding a windshield repair or replacement professional can be harder than think, for the simple reason that many businesses provide the service. If you are approached at the car wash or gas station about repair, it’s OK to say “no.” Mobile service is convenient, but it’s always best to find a local windshield repair shop that has a good reputation and guarantees its work. If your car repair pro doesn’t do windshields, it’s a safe bet he can recommend someone good who does.