You don't measure insurance like that, just like you don't measure whether a wager is a good idea based on how well you happen to do in a single bet, but rather, on the expected value of the average of all possible outcomes weighted by their respective probabilities.

I'm in my early 30s, and up until last year never needed any sort of real medical treatment my entire life. Then I got I to a bike accident, fractured my tibia, almost needed surgery, and was damn glad that I did have health insurance. I could've just as easily not broken my ankle, or it could've been way, way worse. But I don't judge the value of insurance based on whether I happened to need it any given year; that's just dominated by chance.