Renting a car is one of the best ways to explore Europe. It gives you the freedom to leave the major cities, visit smaller towns, and travel on your own schedule. But when you pick up your rental car, there is one decision that can add a surprising amount to the cost of your trip: insurance.

Before automatically accepting the insurance offered by the rental agency, check the benefits that come with your credit card. Many credit cards offer rental-car coverage that can protect you against damage or theft, potentially allowing you to decline some of the rental company's optional coverage.

The key is to understand your credit card's coverage before you travel.

Over the years, I have relied on credit card rental-car coverage when traveling, including situations where a rental car was damaged.

My experience has been that when there has been an accident or damage was discovered when returning the car, the credit card companies have stood behind their coverage and handled the claim.

That experience has made me much more comfortable declining the additional insurance offered at the rental counter—but there are some very important rules to follow.

Not every credit card provides the same rental-car protection. Coverage can vary significantly depending on the card, the country where you're renting, the type of vehicle, and the circumstances of the loss.

Before your trip, contact your credit card company or read the card's benefits guide and confirm:

• Which countries are covered. Make sure the coverage applies to every country where you plan to drive the rental car.
• What types of damage are covered. Rental-car benefits may cover damage from an accident or theft, but they don't necessarily cover everything.
• Whether your rental period is within the allowed limit.
• Which types of vehicles are excluded. Certain luxury, exotic, commercial, or specialty vehicles may not qualify.
• Whether the coverage is primary or secondary. This can make a significant difference if you need to file a claim.
• Whether you must decline the rental company's collision damage waiver (CDW) or loss damage waiver (LDW). Some credit-card benefits require you to decline certain rental-agency coverage in order for the card's benefit to apply.

Don't assume that because your card covered a rental in one country, it will automatically cover you everywhere in Europe.

One of the most important things to understand is that you generally need to follow your card's requirements for paying for the rental.

For example, if your credit card's rental coverage requires you to pay for the rental with that card, don't put the rental on one card and then pay other rental-related charges with another card without first confirming that doing so is permitted.

Ideally, use the same eligible credit card for all of the rental charges that the card's benefit requires.

This includes the rental itself and, where required by the card's terms, related charges such as fees or other amounts charged by the rental company.

Why does this matter? Because if you don't meet the card's payment requirements, the credit card company may deny the claim.

This is not something you want to discover after you've had an accident and are facing a large repair bill.

Regardless of whether you purchase insurance from the rental company or rely on your credit card, take photographs and video of the vehicle before leaving the rental lot.

Walk around the entire car and document:

• Scratches
• Dents
• Wheels and tires
• Windshield and windows
• Mirrors
• Bumpers
• The roof
• The interior
• The fuel level
• The mileage

Make sure the photographs clearly show the condition of the vehicle and, if possible, capture the date and time.

If the rental company has documented existing damage, compare its paperwork with your photographs before driving away.

These few minutes can save you a tremendous amount of frustration later.

If you are involved in an accident, follow the rental company's procedures and the applicable local laws. Contact the rental company promptly and obtain any required police or accident documentation.

Then contact your credit card company as soon as possible and start the claims process.

Keep everything:

• The rental agreement
• Credit card receipt
• Photos and videos
• Accident or police reports
• Repair estimates
• Damage invoices
• Correspondence with the rental company
• Documentation showing how the rental was paid

The more complete your documentation, the easier it is to establish what happened and what you are being charged for.

This is another important distinction.

Credit-card rental-car protection is generally designed specifically around the rental vehicle and certain losses involving that vehicle. It may not be the same thing as comprehensive travel insurance.

For example, rental-car coverage may not cover your medical expenses after an accident, lost luggage, trip cancellation, or other travel-related problems.

You need to understand each type of insurance separately.

Before spending hundreds of dollars on additional insurance at the rental counter, check your credit card benefits first.

My own experience has been positive: when I've had an accident or returned a vehicle with damage, the credit card companies have stood behind their rental-car coverage.

But don't take that as a guarantee that every card will cover every situation.

The smart approach is to do your homework before you pick up the car:

1. Confirm that your credit card covers rental cars.
2. Confirm that it covers the specific European countries where you will drive.
3. Understand whether the coverage is primary or secondary.
4. Check the exclusions and vehicle restrictions.
5. Follow the card's rules regarding the rental company's insurance.
6. Use the eligible credit card for the required rental charges.
7. Photograph the car thoroughly before leaving the rental lot.
8. Keep all rental and accident documentation.

The few minutes you spend reading your credit card's rental-car benefits before your trip could save you a significant amount of money—and give you much more confidence when you hand back the keys.

One final reminder: Credit-card benefits and insurance policies change, and the rules are different from one card to another. Always verify the current terms directly with your card issuer before relying on the coverage for an international rental.