I never take the rental insurance as my Credit Card covers the rental insurance. When I was travelling on business, Amex would take of the insurance. When I rent privately, then my personal credit card covers me.
I had 2 no fault accidents abroad and the everything and I mean everything was taken care of by the car rental agency and the credit card company. I never saw any paperwork, phone calls, bills etc etc - a truely positive experience.
Check with your CC company before shelling our for insurance you don't need.
Gerry