I did the same a couple of weeks ago. My car is 14 years old--and has been paid for for many years. The changes I made to the auto insurance will save me over $410 per year.
Our vehicles are 17 and 19 years old (and working great, by the way). But when I analyzed the savings from dropping collision coverage on them against the potential cost of having to pay for the replacement of one of them if "totaled" in an accident, we opted to retain the collision coverage. Particularly since, a little further back, one of our vehicles WAS totaled and it was great to have the insurance company send us a fat check which we used to buy a replacement (same car, same year!).
This, however, is an analysis I did 3 years ago, when the cars still were each valued around $5000, and it would have taken 10 years of insurance premium savings to break even on another collision disaster. So, time to do the analysis again.
(Thanks, OP, for putting the thought in my head!)