When renting a car, should you buy insurance from the agency?

You deplane and head to claim your rental car. But before you snag your ride, you face a barrage of questions about insurance coverage. Should you buy the plans rental companies push? The short answer: If you have a personal auto insurance policy, the plans offered by rental agencies mostly duplicate your coverage.

For a recent Budget rental Checkbook reserved, the base price was $36 per day (plus $26.50 a day for taxes and the usual jumble of fees). Adding “loss damage waiver” coverage (which shifts financial responsibility to the rental company if the car is damaged or stolen) would cost an extra $30.99 per day. Supplemental liability insurance (which covers injuries to others) was $18.32 a day. Personal accident and effects coverage (which pays for injuries to passengers in the car and damage to belongings) would be $9.95 a day.

In total, Budget’s price for “full coverage” was $59.26 a day — almost as much as the cost to rent the car.

These fees are typical: Checkbook checked rates with other major agencies and was quoted prices ranging from $27 to $42 a day just to cover damage to the car; liability coverage added $13 to $16 a day.

Why do so many customers get rental car insurance? In part, lack of information.

Rental companies’ websites typically list brief descriptions of coverage and don’t mention that personal auto policies provide similar coverage.

Another factor: the hard sell. Customer service agents often say things like, “and you’ll want full protection,” as if it’s not optional.

If your personal policy includes collision and comprehensive coverage, it will pay claims for physical damage to cars you rent in the U.S. and Canada.

Similarly, when you rent a car, the liability coverage offered by your personal auto policy covers you for injuries to others.

But your personal coverage probably won’t apply to car rentals outside the U.S. and Canada. And your auto policy is unlikely to cover any rental car for more than a month.

If you rent a vehicle using a credit card, you might get free physical damage coverage — but not liability coverage — from your credit card company. This coverage is standard on many American Express, Mastercard and Visa cards.

If you already have a policy, the credit card company’s plan is secondary coverage. That means the credit card company first will require you to make a claim with your personal auto insurer; most drivers then will get reimbursed for remaining out-of-pocket costs.

When rental companies blame their customers for damage to their cars, they make them liable not only for the cost of repairs, but for revenue lost while the vehicles are out of commission.

These penalties are usually excessive.

You might rent a car for $50 a day, but the rental company could charge you a “rack rate” of $125 or more for each day it takes to repair the vehicle. California, New York and Wisconsin have banned loss-of-use charges for car rentals.

Your personal auto insurance policy might not cover “loss-of-use” charges rental car companies enforce — although insurers are increasingly adding this protection. Many credit cards provide loss-of-use protection but, again, it’s secondary coverage to any personal auto insurance policy.

Physical damage coverage from rental car companies covers loss-of-use penalties but paying an extra $30 to $40 per day to cover the unlikely risk of losing $125 or even $200 per day doesn’t add up.

For example, the European Union requires companies to carry at least 1 million euros of liability insurance on all their vehicles. In other countries, most rental agencies include robust insurance coverage in their rental rates.

For less than $20 a day, companies like Allianz and Travel Guard offer primary insurance policies for rentals. If you don’t own a car, it’s worth considering one of these plans. But note that these policies don’t include liability or loss-of-use coverage.

If you’re an American Express cardholder, consider enrolling in its “Premium Car Rental Protection” program. For a flat fee of $24.95 for each rental you charge to your card, you get primary insurance that covers: