Full glass coverage can be found on both personal and business auto insurance policy. To get the glass coverage you need, you have to purchase comprehensive; a physical damage coverage that would cover theft, vandalism, if you hit an animal or if a tree were to fall on your car. You can then add full glass as an additional coverage on top of this. If you have a situation where a rock hits your window, you would have the coverage you need to fix it, usually with no deductible, as long as the glass was the only damage.
If you’re not sure if you have either of these, talk with your agent! Whether or not you need full glass coverage is up to you. The cost varies so the best way to decide is to talk with your agent about the differences and the ways that this coverage may be helpful to you. Ask your agent about any specific questions you have about what would happen with and without full glass coverage to get a better idea if it’s worth it to get full glass coverage.