My daughter declined the rental car company's car insurance because she carries full coverage on her car. This morning a rock kicked up off the highway and broke the windshield. Is she liable for the replacement?

Your daughter made a reasonable choice to decline rental car insurance if it would have duplicated her own car insurance coverage.

As long as she has collision and comprehensive coverage, her car insurance should apply if the rental car were damaged in an accident or by some other cause, such as vandalism, theft, collision with an animal or, in her case, a stray rock breaking the windshield. However, your daughter will still have to pay her deductible. Have her call her insurance company or agent to get details of her coverage and instructions on how to file the claim.

Before renting a car, it's always a good idea to review your car insurance policy to make sure it provides adequate coverage. Otherwise, it's easy to get talked into purchasing extra insurance you don't need at the rental car counter. Conversely, you may end up foregoing essential coverage just to save a few dollars. Call your insurance agent or company for coverage details, and check whether you have rental car insurance coverage through one of your credit cards. Many credit card companies offer rental car insurance benefits for free if you use your credit card to charge the cost of the rental. Using your own coverage is often less expensive than purchasing insurance from the rental car company.

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Customers who want to rely on credit card insurance should get details about the coverage in writing, according to the Insurance Information Institute (III). Credit card insurance coverage varies widely from one company to the next, and some policies cover only damage to the rental car but not to other cars. Others don't offer personal liability coverage for bodily injury or death claims.  Compare credit card offers by visiting sites like CardRatings.com or Best Credit Cards 2012 to learn more about current credit card deals and the coverage they offer.

The rental car company's insurance offering is worth the money if you've dropped your comprehensive and collision coverage or don't own a car and therefore have no car insurance.

For more, see the basics of rental car insurance.