Full coverage vs liability-only auto insurance

No policy form anywhere is titled full coverage. The phrase is shorthand, used by lenders, agents and drivers alike, for an auto policy that carries liability coverage plus the two physical damage coverages, collision and comprehensive, that pay to repair or replace your own vehicle. A liability-only policy carries the parts that pay other people and leaves your own car uninsured against damage.

The question of which to buy is therefore narrower than it sounds. Liability coverage is not optional in any of the four states we serve; every registered vehicle has to carry it. What is optional is whether you insure the car itself, and that decision is mostly arithmetic about the car's value, your deductible and what you could absorb if it were destroyed tomorrow.

What liability-only actually includes

A liability-only policy pays for injury and property damage you cause to others, up to the limits on the declarations page, and pays for your legal defence if you are sued over an accident. It says nothing about your own vehicle. If you hit a pole, a deer or another car, the repair to your car comes out of your pocket. If someone else hits you and is at fault, their liability coverage pays for your car, which works only if they are insured, findable and carrying enough limit.

Depending on the state and the carrier, a liability-only policy may also carry uninsured and underinsured motorist coverage, medical payments coverage, and in Utah, personal injury protection, which is required under that state's no-fault system. Those coverages pay for injuries to you and your passengers. They are frequently bundled into the phrase liability-only even though they are not liability coverages at all, and they are worth far more than their premium suggests.

What collision and comprehensive add

Collision pays to repair or replace your vehicle after it strikes another vehicle or object, or rolls over, regardless of who is at fault, less your deductible. Comprehensive pays for almost everything else that can happen to a parked or moving car that is not a collision: theft, vandalism, fire, flood, hail, a windshield cracked by a rock on the interstate, a rodent chewing through wiring, and the animal strike that so many drivers assume is a collision claim but is usually handled under comprehensive.

Both coverages pay the actual cash value of the vehicle at the time of loss, not what you paid for it and not what you owe. That single fact drives the whole decision. A car that has depreciated to a small value cannot produce a large claim, so the premium for insuring it buys a correspondingly small benefit. If you owe more on the loan than the car is worth, the shortfall is the province of gap coverage, a separate addition that neither collision nor comprehensive supplies.

The mechanism that actually differs

Liability coverage is priced on the harm you might do to others, which does not shrink as your car ages. Collision and comprehensive are priced on the value of the car and the odds of it being damaged or stolen, which fall as the car depreciates, but not as fast as the value falls. The premium for physical damage coverage on an old car can therefore be a large fraction of what the car would pay out in a total loss. There is a point in every car's life where the expected benefit of insuring it no longer justifies the premium, and finding that point is the whole exercise.

There is a second difference. A liability claim against you is unbounded by anything except your limits and the court; a physical damage claim on your own car is bounded by the car's value less the deductible. Money moved from physical damage coverage to higher liability limits often buys more protection for the same premium once a car has aged.

A worked example

Suppose a driver in Reno owns a twelve-year-old sedan with an actual cash value of $4,000 and no loan. Say collision and comprehensive with a $1,000 deductible add $600 a year to the premium. The most those coverages could ever pay is $3,000, the value less the deductible, and only if the car is destroyed or stolen. If the car went five years without a claim, the driver would have paid $3,000 in premium to insure a benefit that never exceeded $3,000. Dropping to liability-only and putting the $600 a year into a repair fund is a reasonable decision for this driver, provided the fund actually gets built.

Now suppose the same driver replaces the sedan with a three-year-old crossover worth $28,000, financed with $24,000 still owed. Collision and comprehensive with the same deductible might add $900 a year. A total loss without them would leave the driver making payments on a car that no longer exists. Here the coverage is not a judgement call; the lender will require it as a condition of the loan, and it would be wise even without the lender. All figures are illustrative.

Who each suits

A short decision rule, in order.

• If there is a loan or a lease on the vehicle, carry collision and comprehensive. The finance contract requires it, and a lapse invites the lender to force-place coverage at a much higher cost.
• If losing the car outright tomorrow would be a financial emergency rather than an inconvenience, insure it, whatever its age.
• If the car's actual cash value is small and the annual premium for physical damage coverage is a large fraction of the value less the deductible, liability-only plus a repair fund is defensible.
• If you live where hail, theft or animal strikes are common, consider keeping comprehensive alone even when you drop collision. Carriers price the two separately and comprehensive on its own is often modest.
• Whatever you decide about the car, do not fund it by lowering liability, uninsured motorist or medical coverage. Those pay for people, and people are more expensive than cars.

Regional notes

In Arizona, Nevada and Idaho, fault decides who pays for a crash, so a liability-only driver hit by an uninsured or underinsured motorist has only their own uninsured motorist property damage coverage, where offered, or their own funds to repair the car. Uninsured driving is a real exposure in all three states and a good reason to carry the uninsured motorist coverages even on a liability-only policy. In Utah, the no-fault system means your own personal injury protection pays your medical bills first regardless of fault, but property damage to your car still follows fault, and the same uninsured motorist logic applies.

Comprehensive matters more than people expect across the region: hail along the Wasatch Front and in the Treasure Valley, monsoon flooding and dust storms in the Phoenix and Tucson basins, catalytic converter theft in every metropolitan area, and deer, elk and open-range cattle on rural highways in all four states.

When to keep what you have

If your vehicle is financed, you have collision and comprehensive, and the deductible is one you could pay tomorrow, there is nothing to change. If you own an ageing car outright and still carry physical damage coverage, the right move is often not to drop it but to raise the deductible, which reduces the premium while keeping protection against the total loss that would actually hurt. Dropping coverage only to add it back later can also reset the loyalty and claims-free credits some carriers give, so the decision is worth making once and deliberately rather than toggling year to year.

How to use this

Send us the declarations page and the vehicle's year, mileage and loan status. We can look up the actual cash value, separate the physical damage premium from the rest, and show what liability-only, a higher deductible or the current setup would cost across the carriers we represent in Arizona, Nevada, Utah and Idaho. Where the current policy is already the right shape, the analysis says so and nothing changes.