Windshield replacement is necessary when you get a crack in your wind bonnet that is large enough that it obstructs your view of the highway.
Sometimes windshield replacement is necessary when a crack in the glass does not create a visibility problem but instead poses a threat of allowing the glass to break even farther and possibly fall out of the car. If you want to know more about windshield replacements then you can check out: McConnell auto glass – Glass replacement
A windshield replacement will need you to find another piece of glass that's shaped just like the one that you have. The glass from one model and make of car will usually not be appropriate as a windshield replacement within a different auto. Each maker shapes the glass that they set before the motorist a bit differently.
The government regulates the manufacture of glass that will be set in cars and in commercial buildings. All glass that's meant for these functions have to be heat hardened so that they are resistant and less brittle. The procedure which makes them become resistant also leaves them too difficult to be shaped or cut subsequently.
Before these things can be replaced you'll also need to have a replacement gasket that fits round the opening. The gasket is going to be made from rubber and it'll match the opening from the automobile. It is going to also match the part of glass protecting the borders of the glass out of vibrations which could make it be broken.
You've got to get a unique adhesive to use to bind the glass into the rubber and the rubber into the automobile body.