Health Insurance?

I'm doing an assignment on health insurance and I wanted to know why is it a good thing to get health insurance?
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The purpose of any type of insurance is to protect against catastrophic loss. Using health insurance as an example, most everyday medical expenses are not very expensive (a physical exam averages $150.00+/-), but if you are admitted to the hospital for an emergency your medical bills would be in the tens of thousands of dollars at a minimum. If you do not have insurance you "self-insure" againts that potential catastrophic loss. Without insurance, the average person would face financial ruin if faced with a major loss.
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