12/12/2014 07:30 am ET Updated Dec 06, 2017

Hurry Up! Big Obamacare Deadline Coming Monday

The first Obamacare enrollment deadline for next year is just three days away, meaning Monday is the last day for people in most states who buy their own health insurance to choose a plan they can begin using Jan. 1.

If you're already a customer of a plan selected from a health insurance exchange marketplace or directly from an insurance provider, or if you're uninsured now and looking for coverage for the beginning of the year, there's no more time to waste. Here's are some don't's and do's that last-minute health insurance consumers should consider before the deadline in your home states.

"Don't wait until Sunday. Don't wait until Monday after work," said DeAnn Friedholm, the health care reform campaign director at Consumers Union. "It is complicated."

Don't delay!

If you're one of these people and don't visit or your state's exchange, you won't be able to get a new plan until February, and the last chance to choose a plan for any part of next year is Feb. 15 (except under special circumstances). Five state's exchanges have different deadlines: Dec. 18 in Maryland and Dec. 23 in Idaho, Massachusetts, Rhode Island and Washington state. These deadlines only apply to people who buy health insurance through an exchange, a broker or directly from an insurer -- not those who get health benefits from their jobs or a government program like Medicare or Medicaid.

There are a lot of factors to consider, like what doctors and hospitals you can access, what drugs and medical services are covered, how much you'll have to pay out of pocket when you get health care, and what the monthly premium is. Sorry -- there will be some math.

To prepare, you should have some information and documentation handy, like your family members' Social Security numbers and last year's tax returns or something else to verify your income, which is how subsidies are calculated.

Don't Stand Pat!

Maybe you got a really good deal on the health insurance you have now, and you like it, so you figure you're all set. While it's true that the health insurance exchanges in most states (check with the exchange to find out about where you live) will automatically roll you into the same plan for next year if it's still available, there are a lot of good reasons shop around.

"Don't assume because you have something from last year that it's still the best value for you," Friedholm said. "There are real savings here to be had for many, many people." The Department of Health and Human Services estimates that more than 70 percent of current Obamacare enrollees could save money next year by switching to a new plan with a similar level of coverage.

Monthly premiums for exchange policies are going up and down all over the place and there are new plans on the marketplaces. It's smart to check whether you can find something more affordable.

Don't assume you don't qualify for financial assistance: 85 percent of this year's Obamacare enrollees did, and tax credits are available to people who earn up to four times the federal poverty level, or about $94,000 for a family of four.

For those who get subsidies, shopping is crucial because of the complicated way the tax credits are calculated. The value of the subsidy is linked to the cost of the so-called benchmark plan in every geographic area, and those prices went down in many places. These lower premiums mean smaller subsidies. Even if the sticker price for your current plan isn't going up much, you could end up paying much more by not finding a less expensive alternative because your tax credits will be worth less. (Read a more detailed explanation here.)

If you are automatically renewed into your existing plan and get a scary bill for January, you can switch to something else for the rest of the year, but you're stuck with that plan for at least a month (unless you cancel it outright and go without coverage).

It's also vital to visit or a state exchange to update your household's income information. If you expect your income to rise and you and don't notify the exchange, you may have to pay back part of your subsidy.

Do Your Research!

The plan you have now may have changed in ways other than price. Your doctor or hospital may not be in the network anymore, or may be available through a different plan. The amount you pay when you get health care may be different, as might the services the policy covers. The journalism nonprofit ProPublica created a useful tool that helps you compare benefits in this year's insurance plans with next year's. Find it here.

The trickiest thing about choosing insurance is finding a balance between a decent monthly premium while not exposing yourself to out-of-pocket costs like deductibles and copayments you can't afford. For example, if you know you'll have frequent or big-ticket health care needs next year, it may make sense to pay a higher monthly premium so your out-of-pocket costs are lower, Friedholm said.

Do Ask For Help!

To get information about the basics, like what health insurance jargon means or what factors you should consider when choosing a plan, try the Consumer Reports Health Law Helper. The exchanges also have telephone hotlines, and can direct you to in-person help at no cost in your community. Private insurance brokers also can assist consumers at no charge.

To see an estimate of how much your health insurance might cost, use this calculator from the Henry J. Kaiser Family Foundation:

CORRECTION: An earlier version of this story misreported the deadlines in five states. The post has been updated.