Image: Doctor talking to patient © Jason Butcher, Cultura, Getty Images

Open enrollment is that magical time of year when you get to confront how little you understand about your company's benefits.

Do you have the right health insurance plan? Should you contribute to a pretax flexible spending? Is vision insurance worth the cost? And holy cow, look how much will be coming out of your paycheck to pay for all this!

It's very, very tempting just to default to the same benefits we had last year. Doing so, though, can cost us big time. Premiums are rising, health insurance options are changing, and what suited us once may no longer be the best choice. Employers pay thousands of dollars each year to provide these benefits, and so, typically, do we. We really owe it to ourselves to think through the options.

"There are so many changes going on that you don't necessarily want to stay where you are without at least seeing what is available," said Craig Rosenberg, a national practice leader for Aon Hewitt's health and welfare benefits administration business. "There might be something that's a better fit."

Comparing your health insurance options should be easier this year, thanks to new rules that require employers and insurers to provide you with "clear, understandable and straightforward information" that summarizes health plan benefits and coverage. The rules, which stem from the health care reform law, should make it easier to make "apples to apples" comparisons, Rosenberg said.

Another change under the health care reform law (often called Obamacare) is that new policies must provide many preventative services -- including mammograms, blood pressure screening, many immunizations and colonoscopies for people over 50 -- for free without your having to meet a co-payment or deductible. You'll find a complete list of covered services on the HealthCare.gov website. The change applies to policies issued since September 2010. If your employer hasn't made substantial changes to your health insurance coverage, the policy may be "grandfathered" and not required to add preventative care until 2014. Ask your human resources department or the insurance company if you're not sure what's covered.

Image: Liz Weston

Liz Weston

As you're pondering your choices, here are some factors to consider:

  • Are your doctors part of the health plan's network? If not, are you willing to switch to providers who are?
  • If you regularly take prescription drugs, are they covered by the plan? If you take brand-name versions and they aren't covered, are you willing to switch to generic versions?
  • How do the costs of the various options compare? You can use an online calculator provided by your employer, or this one on Money-Zine.com, to help with the math. (You can find most of the requested numbers by reviewing the "explanation of benefit" forms provided by your insurer after each claim.)
  • Will you face any new health-related expenses next year, such as maternity care, extensive dental work or orthodontia? Factor those in when perusing your insurance options.

Here's some more information to help with your choices:

Health insurance if you're single

Healthy singles often can save some money by opting for the high-deductible plan, if one is offered. These plans often have the lowest premiums, but the first $1,000 or so of medical spending comes out of your pocket. Some employers soften the blow by offering -- and sometimes partly funding -- health savings accounts that allow you to save pretax money to pay the deductible. Some also offer health reimbursement accounts, which are funded entirely by the employer and which also can help you pay out-of-pocket medical costs.

High-deductible plans are not a good fit, though, if:

  • You have no savings.
  • You'll skip needed medical care because you have to pay for it yourself.
  • You're not in good health.

If any of those are true, you should consider your employer's other plans. HMOs often are the less expensive option if you're willing to stay within the health maintenance organization's network of providers. If you want more freedom to choose your doctor, look for the PPO, or preferred provider organization, option, but be prepared to pay more. Some employers provide an in-between option called a POS, or point of service, plan, that gives you the choice of paying more to use providers outside the network as long as you get a referral from an in-network primary physician.

Health insurance if you're married.

If your spouse also has employer-provided benefits, you'll need to do some math to see if it makes sense to put both of you on one plan and, if so, which one.

Review how much you've spent on health care this year, including premiums, co-pays, deductibles and out-of-pocket expenses. You can use one of the calculators noted above to compare what you'd pay under each plan.

Once again, high-deductible plans may be a good choice if you're healthy and have the savings to pay for the first $1,000 or so of care. Otherwise, HMO and POS options are often cheaper than a PPO, if you're able to live with the restrictions.