I often do not take the optional car-rental insurance, costs me more
money....

that's ok as long as you don't have anything unplanned happen...

I was on vacation was driving a long and hit a birdge in Mendocino County
along the 101 in Northern California had to pay National Car Rental $6000
for the car and the county to repair the bridge....for some unknown reason
my insurance refused to cover...

I hate insurance companies.. they take your money but when you need them,
the often weasel out or find some disclaimer to wave at you