You are looking forward to a well-deserved vacation. After planning your flight and hotel, the next task is renting a car. Rental cars are a fun time to try out driving something a little different than your normal vehicle, but as you go through the questions with the representative or online, the question of insurance comes up; would you like to buy their insurance or does your insurance cover the rental? Depending on where you are renting a car, the type of vehicle along with your current automobile coverages can determine if your coverage will extend to the rental vehicle. 
Most auto insurance companies provide extensions to rental cars if the vehicle is rented in the United States or US Territories. If the vehicle being rented is a commercial vehicle (a moving truck is one of the most common non-personal vehicles) then coverage generally does not extend. Any exotic or high-end vehicles are generally not included in this extension of coverage either, because the value of these vehicles is generally much different then the value of a vehicle in line with your personal coverage.
Another important consideration is to determine which of your specific coverages will extend to the rental vehicle. If your policy has comprehensive and collision coverage, then these coverages would be mirrored on your rental vehicle with the same deductibles.
If you have not rented a vehicle recently or if you are unsure whether you should get additional coverage for your rental, a quick call to your local agent can be a great way to make sure you are covered in the event of a claim. Some companies do have endorsements for coverage outside of the United States in countries such as Canada and Mexico if you are planning an international trip!
P.S.- Trip insurance is always recommended, especially for larger trips, to make sure that you and your funds are covered. When you call your agent to discuss your rental vehicle, it is a great time to review trip insurance options, too.