Mark Fitzpatrick is a senior content director at MoneyGeek, where he writes about insurance and other financial topics. He has a strong understanding of the economics behind insurance, and he’s passionate about using that knowledge to bring transparency to personal finance decisions. Essential Knowledge In Car Insurance is his first book.

Comprehensive

Comprehensive coverage is an important piece of car insurance because it reimburses you for damage done to your vehicle by non-traffic related incidents. These include weather events, falling objects (like tree limbs), theft and vandalism. While these incidents are typically less common than a car accident, they can be just as expensive to repair or replace. Also, if you lease or finance your car, your lender may require that you carry comprehensive coverage to protect their investment. Comprehensive does not cover medical bills for you or others, so collision and property damage coverage will likely be necessary if you are involved in an accident.

This article was originally published on December 14, 2016 and has been updated. NerdWallet is a personal finance website that helps people make better decisions about money.

Uninsured/Underinsured Motorist Coverage

Uninsured motorist coverage, also called UM or UM/UIM, spares you the cost of injuries and damages from crashes caused by drivers who don’t carry car insurance. It’s required in some states, and it’s usually a relatively inexpensive add-on to your policy. It’s worth it because, if you’re in an accident with someone who doesn’t have insurance, their damages could easily exceed your limits. Adding this coverage could help you pay for things like medical bills, pain and suffering, lost wages, funeral costs and more. It can even protect you in cases of hit-and-run accidents.

In some cases, it’s possible to “stack” your UM/UIM coverage with the liability coverage in your policy. This can allow you to take advantage of the higher limits available with certain insurers. However, it’s important to note that not all states allow stacking.

If you want to make sure that your UM/UIM coverage is as high as possible, it’s a good idea to get a quote for full-coverage auto insurance. That way, you’ll be able to see how much you can possibly get covered under the terms of your current policy.

While it may seem like a no-brainer to have liability coverage in place, the truth is that most people on the road don’t. While a large majority of drivers do carry car insurance, there are still plenty of people who don’t — and sometimes they’re the ones who cause accidents that can be costly for everyone involved.

This is why it’s so important to have an understanding of the different types of car insurance available and how they work. Liability is the most basic and mandatory type of car insurance in all states, but there are a number of other options you can choose from to provide more protection for yourself on the road. Medical payments, collision and uninsured/underinsured motorist coverage are all ways to do this, but they each have a slightly different focus. Liability and comprehensive are often bundled together as full-coverage auto insurance, while collision is separate from uninsured/underinsured because it covers damage to your own car that you cause (like when you slam into a telephone pole). The other option is uninsured/underinsured driver coverage, which protects you against the at-fault drivers who have no or inadequate liability coverage.