You may know that dental or vision-related expenses are not covered by your health care insurance, but that's probably not all. Pre-existing conditions have long been excluded by many insurers, though President Obama's health care reform act is addressing that. A nose job or other cosmetic surgery, for example, is most likely excluded, too, no matter how much of an emergency you think your double chin is.
Your policy may also not cover ambulance services, maternity care, prosthetics, kidney dialysis, organ transplants, diabetes management, emergency-room visits, mental-health care, and care you receive outside the United States -- or any of a number of other expenses. Don't be overly alarmed -- policies vary widely, and you may be covered for many of the above costs, at least to some degree. Just be sure to find out what is and isn't covered, and when shopping for a policy, seek out the one that fits your needs and pocketbook best.