Unfortunately when it comes to any sort.of insurance, many do not know what they have until it's needed. It's a buyer beware game. Generally speaking, "retail" insurance companies like State Farm, All State, Progressive, etc. use the underlying assumption of market value of an OEM equipped vehicle when settling a claim. That's because if an OEM vehicle is worth $10K and you put on $10k of modifications, they won't base the claim on $20k because you've only been paying premiums based on the OEM value. Anything above and beyond you need a "boutique" policy like Haggerty that has been mentioned to insure up to the true value.
It's always a good idea to sit down with your agent every few years to review your coverage and make sure it's relevant to current conditions. Homeowners for example, you set the value of the home on the day you execute the policy. You live in the house for 10 years and market values have increased by 15%. You have a total loss from a fire and now.you find that you've been under insured all this time. On top of that, you find out you were only paying for depreciated value vs. replacement value. You're screwed. Same for jewelry, a base policy will cover jewelry up to a nominal amount. Anything above that amount you need to have written into the policy and.pay additional premiums for that additional coverage. You had a sports card collection...out of luck because a base policy won't cover it...should have had a separate policy on it all along. For auto a classic example is lost wages due to injury. Once again you set the base policy years ago and in the meantime you income has risen but you're not covered up to that level...screwed again.
Be extremely careful with the companies like the General, Liberty Mutual, etc. that promote state minimum requirement policies. They will carve out individual pieces of coverage to lessen the cost of the premium. The problem is that you have an accident and your policy is stripped down and won't cover the.damahes/injuries. You'll end up.losing a lot more than the money saved on the annual premium reduction.
It comes down to that old saying ....you get what you paid for. Always know the details before signing the bottom line.