Auto insurance is both legally and personally necessary. Auto insurance is required by the state to cover liability, that is, the state wants all drivers to be able to pay for damage they do to other people or their property. Since automobile accidents involving injuries can be extremely expensive, very few people could pay for such damage out of their own pockets and must buy insurance to guard against those expenses. Auto insurance is also required if the driver has lien on his car. If the driver is involved in an accident causing damage to his vehicle, his mortgage company wants him to have insurance coverage to pay for that damage; he should also have comprehensive coverage for such events as theft, hail damage, or vandalism. If a driver does not carry insurance, the company holding a note on his vehicle may purchase insurance for that car on their own, and it is usually much more expensive than any options the driver might find.