Open enrollment on most of the Affordable Care Act exchanges ends Friday at midnight (Pacific Standard Time). If you don't get your insurance through your employer and are still considering buying your own, there are some important things to know before the deadline.

So far, nearly 5 million people have enrolled in health insurance plans sold through the 39 federally run HealthCare.gov platform.

That number doesn't include people in the 11 states and Washington, D.C., that run their own exchanges, many of which are seeing robust sign-up numbers. Nor does it include people who already have ACA insurance and are automatically re-enrolled in the same plan or an equivalent one if they do nothing. Plans for about 1.6 million people were auto-renewed in 2017.

Still, the total number of enrollees is unlikely to match the 9.2 million people who signed up in 2017, when the enrollment period was twice as long and there was a well-funded outreach effort by the federal government.  

More About Health Insurance

For those who want to continue buying their insurance through the ACA marketplace, declining enrollment is a troubling sign.

“The people who aren’t signing up are mostly likely healthy people," says Chris Sloan, senior manager in the policy practice at Avalere Health, a healthcare consulting company. "You don’t stop buying health insurance if you have a chronic health issue.” But when healthy people start leaving the marketplace, the proportion of sicker people to cover is higher, causing insurers to raise rates or exit the market.

Sloan doesn’t expect the ACA markets to collapse. “Millions of people who are subsidized will continue to buy health insurance,” he says. But if the numbers continue to drop because healthy people want to go without insurance and others can’t find an affordable option, “that’s not a good trajectory.”

For now, the ACA exchanges are intact as the open enrollment deadline nears. Here are four things you should know if you want to buy insurance for next year:  

You May Have More Time

The sign-up deadline is midnight (PST) Dec. 15 for the 39 states with exchanges that are run through the federal HealthCare.gov site. But some states that operate their own exchanges are extending the enrollment period. The Maryland Health Benefit Exchange announced that it will give residents an extra seven days to sign up, moving its deadline to Dec. 22. Enrollment on the exchange has outpaced last year’s, but officials say they want to avoid a last-minute crush.

Maryland joins nine states and Washington, D.C., that earlier announced longer open-enrollment periods. California, New York, and D.C. have the longest, running through Jan. 31. That was the end date for all ACA-related open enrollment in the last few years. Check here to see your state deadline.

Procrastinators may also be given more time. In previous years, HealthCare.gov had “waiting rooms” during high-traffic times where consumers waited for access to the online exchange. For those caught in the waiting rooms when the deadline passed, enrollment was extended for a few days.

The Centers for Medicare and Medicaid Services, which oversees the exchanges, hasn’t announced yet whether it will offer a similar extension this year. 

Consumer Reports is working with WNYC-New York Public Radio to educate consumers about their options during open enrollment. Find out more at We’ve Got You Covered.

Extra time may also be granted in some special situations. If your 2017 plan is no longer being offered, you have 60 days from Dec. 31, when the plan ends, to choose a new one. You can wait as late as March 1 to enroll in a 2018 plan.

That scenario is more likely this year because insurers exited from many markets. The average number of issuers per state dropped from 5 in 2014 to 3.5 for 2018, according to the Kaiser Family Foundation, a health-policy research nonprofit.

If you’re in a hurricane-affected area, you have until Dec. 31 to sign up. The special enrollment period applies to people who live in counties deemed hurricane-disaster areas by the Federal Emergency Management Agency. That includes counties in Texas, Florida, Alabama, and Louisiana, as well as people in the U.S. Virgin Islands and Puerto Rico who came to the U.S.

If you think you're eligible for a special extension, you'll have to request one at HealthCare.gov.

Plans May Be More Affordable Than You Expected

Premiums on the most popular ACA Silver plans are up an average of 34 percent from 2017, according to Avalere Health.

But about 80 percent of people who enroll in plans through the ACA exchanges won't feel that steep price hike because they're eligible for subsidies to help pay their premiums. That's up slightly from the number of people who got subsidies in 2017.

In fact, the financial help for those people is likely to be even more generous for 2018 because as premiums increase, so do government subsidies. The financial subsidies are based on the cost of the most popular Silver plans, which are up significantly in many places around the U.S.

That’s why it’s critical to actively compare plans and not default to the same plan through auto-enrollment, says Karen Pollitz, a senior fellow at the Kaiser Family Foundation.

“Most people who shop around can find lower cost plans,” she says.

But because many insurers raised rates the most on Silver plans, more comprehensive Gold plans that typically have higher premiums could be a better value, because out-of-pocket costs are lower in a Gold vs. Silver plan.

Many people will also find Bronze plans to be much cheaper and in some cases free because their subsidy may be large enough to cover the entire premium. If you choose a Bronze plan, though, the deductibles will be higher than on Silver or Gold, so be sure you can afford to pay them.

If you need to go to a doctor for care beyond preventative services, you’ll usually have to pay out of pocket until you meet the deductible before your insurance begins to pay some of the bills.

If your income is low enough, you may also qualify for help paying out-of-pockets costs such as deductibles and co-payments. But you can get that help only if you buy a Silver plan in an exchange. If you qualify for this extra help, a Silver plan is going to be the best option, Pollitz says. 

You May Have Other Options (Cheaper Ones, Too)

Still, the millions of people who buy their own health insurance and don’t get financial help are facing premium sticker shock. If you're one of them, there are other options you should research.

You might find a more affordable plan buying off-exchange, that is, directly from an insurance broker or insurance company. Some insurers boosted their premiums the most on plans they're required to subsidize on the ACA exchanges, so plans sold off-exchange with the same coverage may be cheaper.

You might be able to buy a less-expensive group plan through a professional association, trade or alumni group, or other membership organization. Because you're pooled with the other members of the organization, you get a group rate, which may mean lower premiums. You have until the end of the year to join such a plan.

For other ways to make your insurance more affordable, see our article here.

You’ll Still Face a Penalty If You Don’t Have Insurance

Congressional Republicans, with the support of President Trump, want to eliminate the penalty for not complying with the ACA’s individual mandate, which requires most people to buy health insurance or pay a fine, which could be thousands of dollars a year.

The GOP tax-reform legislation, expected to be voted on next week, reduces the penalty to zero. But even if tax reform is signed into law, the elimination of the penalty won't take effect until 2019. So unless the change becomes retroactive, if you don’t buy health insurance for 2018 you may still be on the hook for the penalty.