The moment you get a crack in your windshield then a windshield replacement or repair is necessary. Windshield replacement is also necessary even when the crack in the glass does not create a visibility problem because if the crack is ignored, the glass can break farther and end up falling out of the car.
Replacing the windshield means that you should find another piece that is identical to the one you had before. The glass from one model and make of automobile will generally not be suitable as a windshield replacement in another automobile. The glass placed before the driver is always different because each manufacturer shapes them differently. The reason for this is that each vehicle has a slight difference in shape. So it is advisable to buy a piece of glass that was specifically molded for the make and model of your vehicle.
In most countries, the government always regulates the manufacture of glasses and makes sure only the appropriate glass is placed in automobiles and commercial buildings. This means that any glass intended for these purpose must be heat tempered which means they are break resistant and less brittle. The entire process that makes them break resistant renders them too hard. You can neither shape them nor cut them afterwards. Now you understand why a mold must be made to be used as a pattern even before the window is made so that it can fit into the opening perfectly.
You also need a replacement gasket that fits around the opening before any item can be replaced. The gasket made of rubber should fit well the opening in the vehicle. This rubber will protect the edges of the glass from breaking due to vibration. It is important to know that even though tempered automobile glass is very strong, it can easily be shattered especially if you strike it on the edge.
In order to bind the glass to the rubber and also the rubber to the car body, you will need a special adhesive. If you fail to use the appropriate adhesive, the glass will not stay in place and will likely not be water tight. It means you will have a very hard time at the car wash or when it starts raining. The reason for having a windshield is to protect you from flying debris and water. This is only possible if you use the right adhesive.
In some cases, the gasket that holds the glass in place can dry and rot after many years even if the windshield is not damaged. If your vehicle is in such a condition, first you should carefully remove the glass and then proceed to the gasket. Replace the old gasket with a new one then hold the gasket and the glass in place with adhesive.
If you want to save some cash on windshield replacement, you can do this at home but if you think you cannot handle it then you can consult a professional glass company to do everything for you. There are some companies that will even come at your place of work and attend to your vehicle.