We usually buy the insurance through the rental company as I think there is a bigger chance of getting in an accident when driving places, you are unfamiliar with. It makes driving much more relaxed as if the car gets damaged oh well the rental company will take care of it and it won't affect my personal insurance rates if I do damage the car. The last time my wife rented we booked through Expedia and they offered insurance for a pretty good price so we bought it. Unfortunately my wife hit a rock on the narrow roads in Wales and put a dent in the bumper. Enterprise took a 2000 pound deposit for the damage. We have got most of it back but the Expedia insurance didn't cover loss of use and Enterprise is trying to charge me for 16 days of loss use. I am still trying to get them to knock that down to a reasonable number of days. Very much wish we had gotten her the insurance directly through Enterprise would have made everything much simpler. I understand that for longer rentals it can really add up but for just a day or two I think it's so much more comforting to just get the rental car insurance from the agency.