On his podcast, Clark Howard answers real reader questions on money, credit, debt, retirement, travel, and more, along with co-host Christa DiBiase.

Clark's answer: You are definitely onto something here. When I talk about using a credit card to provide rental protection – specifically cards that offer primary versus secondary coverage – we are strictly talking about damage to the vehicle itself. The primary push for those cards is Collision Damage Waiver (CDW) or Loss Damage Waiver (LDW), which only applies to the rental car you are driving.

Then you have the secondary issue, which is liability. If you get into an at-fault accident, your personal auto insurance typically covers you for the temporary use of a rental car. Most people's policies do, though not all. In that scenario, your insurance steps in to handle the liability claim, even though they won't have to pay to repair the rental car if you used a primary coverage credit card.

The key rule is to always check with your auto insurer before you travel to verify that your policy covers temporary use of a rental car. The liability risk in an accident is significant enough that if you had to buy a standalone liability policy on the open market, it would be crazy expensive per day simply because the potential financial risk is so massive and unpredictable.