With all the potholes and damaged roadways around many towns, it's not such a surprise to get nailed by a rock as you drive about. What's important is knowing whether to repair the damage or replace the entire windshield. Getting the problem taken care of quickly may help save you money. Here's an explanation of how that seemingly innocent nick can turn into a bigger problem, and whether your windshield is already beyond help.

Windshields and Rocks

Windshields are made of laminated safety glass. It's really a glass sandwich, with a plastic material sitting between two pieces of glass. That plastic keeps the windshield from shattering when a rock hits it. Instead the rock creates a hole or nick in the glass, often with small cracks. Depending on where they are, small nicks can be repaired. If the damage is too extensive, the windshield needs replaced.

From Little Nicks to Big Problems

Those small nicks and chips can become big problems. Sometimes called "spider webbing," the tiny cracks around the damage grow. Hitting a bump in the road, like a pothole, is enough to cause cracks to expand. Changes in temperature, either outside or inside your car, can also cause expansion. If left unattended, that small nick grows into a maze of cracks that interfere with your vision of the roadway.

Deciding to Repair or Replace

Each state tends to have its own rules about when a windshield becomes unsafe. In California, for example, it is illegal to drive with a cracked windshield or rear window that obstructs the view of the roadway. The determination is often made by a traffic officer on the spot, who may or may not issue a "fix-it" ticket. Many insurance companies do offer windshield protection riders to help with replacement costs. Some insurance firms will even cover the entire cost of repair. Replacing the windshield may or may not require you to pay a deductible.

When to Repair

• A windshield can usually be repaired if the nick is small and there is no "spider webbing" radiating from the site and if that repair can be made without removing the glass. Taking the windshield out usually increases the damage.

• The nick must not be in the driver's main viewing area. Nicks and cracks along the edges may usually be repaired if they haven't reached the seal, the part the holds the windshield in place and keeps it water-tight.

When to Replace

• It's an automatic replacement if the nick is in the driver's line of site or if the rock has damaged both layers of glass. The laminated plastic will keep the windshield from falling apart, but won't keep out moisture. Cars that have antennas or rain sensors embedded in the windshield usually need replaced if either of these features have been damaged.

• If the damage originated inside the vehicle, such as during an accident, the windshield needs replaced. The resulting damage tends to be more severe than a rock created nick, sometimes creating a convex dome shape that places the integrity of the entire windshield at stake.If you do need to replace the glass, try http://www.healyglass.com/.