When they get to the rental counter, many renters are unsure about what to do when it comes to accepting or declining an agency's coverage and waivers. This indecision usually results from not knowing what their personal or business car insurance covers while renting a vehicle. In addition, some credit cards cover damages to many basic types of rental cars. It's a good idea to check into your existing coverage before your trip.
Among some of the reasons for checking your existing coverage before your trip are:

Liability. Most rental car companies will hold you totally responsible for your rental vehicle if damaged or stolen.

Possible savings. These coverage can add up to $10-$25 per day on your final car rental bill. There is really no need to pay for coverage you already have (Note: Some renters may want these coverage to protect their existing personal car insurance premiums/rates).