You're at your typical Rent-A-Car location, you've picked out your vehicle, you're ready to drive it off the lot and then the question comes "Would you like to add our insurance coverage on this vehicle?". That question can lead to a lot of uncertainty and a range of other questions about your auto insurance policy.
Let's help you out!
First, you need to understand what kind of auto policy you are covered under. Is it a commercial auto policy? Then if you're using the vehicle for commercial use you are covered. If you're using the vehicle for personal use then it's not going to cover you. If you're renting a moving truck and that truck weighs over 10,000 pounds then that truck is considered a commercial vehicle and so you will need commercial insurance for it.
Secondly, you need to understand what coverage your policy has. If your policy is a liability only policy then the Rent-A-Car company probably won't be chomping at the bit to hand over the keys and get you behind the wheel of their vehicle. Comprehensive and Collision coverages are usually required by Rent-A-Car companies so that should any accident happen to their vehicle it is fully covered.
Third, who is covered by your insurance policy? Auto policies have drivers listed on them and if there are 4 listed drivers and they all meet the age requirements of the Rent-A-Car company and full coverage is on at least one of the listed vehicles then all 4 of those drivers are covered to drive that rental vehicle.
Lastly if you have Rental Reimbursement/Extended Transportation Expense coverage then your insurance could pay for your rental vehicle. Rental Reimbursement/Extended Transportation coverage works like this: if your listed vehicle is in the shop due to a covered claim and you need a rental until everything is repaired, that coverage is available for you so long as you have full coverage of liability along with comprehensive and collision. So if you back into a fire hydrant and damage your car to the point where it needs to be in the shop for a while and you have RR/ETE coverage then that coverage means you will be reimbursed for getting a rental car.
If you have any questions it never hurts to ask your insurance agent exactly what your policy covers.