Collision-damage waiver, or CDW, insurance is a moneymaker for car rental companies. These optional policies insure you if you get in a wreck or otherwise experience a claims loss while renting a car. The charge for such rental car insurance can add $15 to $25 to the daily cost of a car rental.
The catch is that you may already have protection through your credit card company or auto insurer.
Before leaving on a trip, check with your insurance agent and card issuer to see what kind of coverage you have for car rentals. If your credit card already offers sufficient protection, you could decline the optional coverage. Just be sure to use that credit card when you make your rental reservation.