There are a few reasons why it is important to be covered by auto insurance whenever you're driving a motor vehicle. Here's why:
#1: It's the law. Pursuant to CA Vehicle Code Section 16020 (known as the financial responsibility requirement), it is illegal to operate a motor vehicle without either proof of liability insurance or - if you are self-insured under Section 16052 or a depositor under Section 16054.2 - a certificate of self-insurance or the assignment of deposit letter issued by the department. The purpose of this law is to insure that all drivers have the financial means to compensate anybody who they may injure as a result of their driving. In California, the DMV minimum requirements are currently $15,000 for injury/death to one person, $30,000 for injury/death to more than one person, and $5,000 for damage to property. You should carry insurance because it's the law, and also because it is the right thing to do.
#2: If you are injured in a motor vehicle accident, your personal injury recovery may be limited if you did not have liability insurance at the time of the accident. Pursuant to CA Civil Code Section 3333.4, which was enacted as part of the Personal Responsibility Act of 1996 - Proposition 213 - approved by the voters in November 1996, you cannot recover non-economic damages if you were injured in a motor vehicle accident while in violation of VC Section 16020 (the financial responsibility requirement discussed above).
Recoverable damages in a personal injury case consist of economic damages and non-economic damages. Economic damages compensate you for objectively verifiable monetary losses including medical expenses, loss of earnings, loss of use of property, costs of repair or replacement, costs of obtaining substitute domestic services, loss of employment, and loss of business or employment opportunities. Section 3333.4 has no impact on the recoverability of economic damages. Pursuant to CA Civil Code Section 3333.4, non-economic damages compensate you for pain, suffering, inconvenience, physical impairment, disfigurement, and other nonpecuniary damages. Section 3333.4 bars non-economic damages if you did not have liability insurance (and you were not otherwise compliant with the financial responsibility requirement) at the time of the motor vehicle accident that caused your injuries. In catastrophic injury cases, much of your recovery falls under the category of non-economic damages because of the concomitant pain, suffering, inconvenience, mental distress, emotional distress, physical impairment, and disfigurement. Thus, it is imperative that you protect yourself as well as others by obtaining liability coverage before you get behind the wheel.
As is common in most legal standards, there are certain exceptions to Section 3333.4. Written right into the statute in subsection C is an exception that allows for recovery of non-economic damages if the defendant driver who caused the accident and injured you was convicted of a DUI for the accident that caused your injures. Another exception comes from a California Supreme Court ruling called Horwich v. Superior Court, 980 P. 2d 927 (1999). Horwich seems to limit the statutory bar on non-economic damages to the plaintiff driver who failed to follow the financial responsibility requirement. In Horwhich, the parents of an uninsured driver who was killed in an accident caused by another driver's negligence were able to recover non-economic damages for loss of care, comfort, and society in their wrongful death claim against the negligent driver.
#3: If you do not have liability coverage, then you do not have uninsured or underinsured motorist (UM/UIM) coverage. What happens if you are injured in a motor vehicle accident caused by another driver's carelessness? If you are injured, you should make sure that the police come and write a report to document what happened, you should immediately see a doctor to get treated for your injuries, and then you should call a personal injury lawyer to get you financial compensation for your harms and losses. One of the things your personal injury lawyer is going to do is to find out all possible sources of recovery, including the responsible driver's insurance coverage. If there are no other sources of recovery and the responsible driver was uninsured or underinsured (meaning the insurance coverage is less than what you need to make you whole), then you are going to wish you had UM/UIM coverage.
The way UIM coverage works is that you first resolve your case against the adverse party. If the adverse party has a liability policy that is less than your UIM policy and the adverse party's insurance carrier pays their entire policy, then you have a claim with your UIM carrier for the difference between the adverse party's policy limit and your UIM policy limit. In other words, you do not get to "stack the policies" or add them together. If the adverse party has minimum coverage of $15,000 and your UIM coverage is $15,000, then you do not have a claim with your UIM carrier. If the adverse party has minimum coverage of $15,000 and your UIM coverage is $50,000, then you need to recover the entire $15,000 first before you can get the remaining $35,000 from your UIM carrier. UM coverage comes into play when the adverse party has no insurance at all. In that scenario, you have a claim with your UM carrier, who figuratively "steps into the shoes" of the adverse party.
The reason why UM/UIM coverage is so important is that many drivers unfortunately get behind the wheel without liability coverage or with minimum liability coverage. If you are injured as a result of one of those uninsured drivers' negligence, then you may not have any sources of financial compensation. If you are catastrophically injured as a result of one of those underinsured drivers' negligence, then the $15,000 will not even cover your medical bills.
So there you have it. Those are three important reasons never to get behind the wheel unless you're covered by insurance. Make sure you are covered sufficiently by not only getting liability coverage, but also by getting high UM/UIM coverage so that if you are catastrophically injured you will at least have the financial compensation you will need.