4. You're overinsured

In addition to comprehensive health plans, many employers offer supplemental insurance policies, such as cancer or critical illness insurance, that pay a lump sum of cash after diagnosis. Such policies can provide valuable protection, but they might be unnecessary if you already have broad coverage under your medical insurance and short-term and long-term disability insurance, Goodheim says.

If you're footing at least a portion of the premium bill, why pay for coverage you don't need?

5. You can't afford your share of the medical bills

Low premiums are an attractive feature of high-deductible health plans, but make sure you're prepared to pay all the out-of-pocket medical expenses, Goodheim says.

Besides the deductible, check the maximum out-of-pocket expenses you pay. After you pay the deductible, many plans pay only a portion, such as 70%, of covered medical expenses. Your 30% share is called co-insurance, which you must fork over until you reach the cap on out-of-pocket expenses.

"Those dollars can really add up," Goodheim says.

6. You're expecting, but your policy doesn't cover maternity care

Most employer-sponsored plans cover maternity and prenatal care, thanks to the federal Pregnancy Discrimination Act of 1978 and the Health Insurance Portability and Accountability Act of 1996, as well as many state health insurance mandates for group coverage. Some states also require individual health insurance plans to include maternity coverage, but in states where there is no such mandate, many individual health plans pay only a small portion of the costs or don't cover maternity at all. Even if the plan includes maternity coverage, read the fine print to know exactly what is covered and whether there's a monetary cap.

Starting in 2014, individual and small-group plans sold through state health insurance exchanges must include pregnancy and newborn care, along with other essential benefits.

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7. You don't check your health plan for changes

Scrutinize group health plan offerings from employers each year during open enrollment, Rosen says. Don't assume the plan is still the same. Coverage levels, costs and networks could change from one year to the next, even if the plan is offered by the same insurer.

"If you're not sure about something and it raises a flag in your mind, then check it out," Rosen says.

This article was reported by Barbara Marquand for Insure.com.