You’re driving down the road when it happens: The truck in front of you kicks up a stone. It smacks your windshield hard, leaving a tiny spider web of a crack. You suddenly have a crack in your windshield … what should you do now?

The best advice? Take care of the crack quickly. If it’s a small crack, you can repair it without having to replace your car’s entire windshield. This will save you a significant amount of money. Fixing a cracked windshield might cost you $15 at the low end. Replacing an entire windshield? The cost of that varies widely depending on the type of car you drive. Figure on spending at least $500, though.

You have several options to fix a windshield crack. You can run a quick online search for “windshield repair kit.” This will turn up several pages of results. Most of these kits, which sell for $10 to $20 or so, include a resin injector system. You simply inject the resin into your windshield crack. The resulting repair is invisible to the naked eye. It will also prevent your crack from spreading across the rest of your windshield.

If you are uncomfortable repairing your windshield crack on your own, you can always search your local phone book or the Internet for nearby windshield repair companies. You’ll pay a bit more. But you’ll be guaranteed a quality job. And working with these companies is still far less expensive than is replacing an entire front windshield.

If you ignore that tiny crack, here is what will happen: Your crack will begin to grow. Before long, it will spider web across your entire front windshield. This is dangerous. Depending on the crack’s location, it could hamper your vision while driving. It’s also illegal. If a police officer stops you for speeding or another moving violation, that officer can also write you a ticket for driving with a broken window.

Needless to say, this can be quite an expensive infraction. Add a $250 ticket to the $500 cost of replacing your windshield, and you’re looking at quite a hit to your wallet. That $15 repair kit sounds a lot better, doesn’t it?

Next time you see a crack start in your front windshield, don’t delay: Get that crack repaired. A windshield crack is a small problem. Unless it’s ignored. It then becomes a big, and expensive, one.