This has been the conventional wisdom, raise the deductible and drop collision/comp coverage on older vehicles. I don't believe this still applies today.
I looked at raising my deductibles from $500 to $1000. It was going to save me like $20 a year. So I would eventually break even after 25 years. It doesn't make financial sense. The same thing with my house insurance, was going to raise deductible from $1000 to $2500, and it was only going to save $40 a year. A 37 year break even period? It just doesn't make sense.
I also got quotes from several other companies and it didn't make sense to switch either. Insurance is a racket without a doubt. I just hope if I ever do truly need it, that is actually works the way it should.
Dropping insurance on an older car? Well maybe, but you have paid so much for comp/col over the years, why not keep it this way if something does happen then you will at least get the value of the car.
Maybe I am wrong, but that is my opinion and what I am doing.
I'm not disputing you, just trying to figure out what you're saying. If you only pay for liability you don't have a deductible. Also, consider the difference between collision and comprehensive. While the former covers your vehicle if you have an at-fault accident; premiums for the latter is generally a pittance, while covering theft, vandalism, glass breakage and other "Acts of God" such as deer collisions which you can't reasonably prevent; and normally won't go up if you have a claim.
Results can vary depending on state... I know that Mass. and NY are "No Fault" states. Don't ask me what that means except that after working as a sub contractor for 10 years my insurance company found out that I occasionally worked in NY. (about 2-3 weeks/year) My GL policy jumped from <$300 to >$1800 per year; my truck policy went from affordable to-
well, let's just say I couldn't sit down for a week.