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Since open enrollment began on Nov. 15, almost 1.4 million people have signed up for health coverage through the federal insurance exchange, and another 183,000 through state exchanges. With nearly 7 million people already participating, signups are on pace to meet the government's projection of 9 million enrollees in 2015, according to the Kaiser Family Foundation.

If you're one of the many who still need to enroll for 2015 coverage, here are five keys things you need to know before you visit your state's health exchange website.

1. If you want health insurance on Jan. 1, you must enroll today. You still have until Feb. 15 to buy a 2015 plan, but you will have a gap in coverage if you enroll after today’s deadline. Coverage begins on Feb. 1 for people who enroll between Jan. 1 and Jan. 15. Sign up between Jan. 16 and the end of the month, and coverage won’t begin until March 1.

2. Some states are giving you more time and extending the deadline to get coverage by Jan. 1. For example, New York and Idaho’s exchanges will allow users to sign up until Dec. 20. To find out whether you're eligible for an extension, visit your state’s marketplace exchange website through healthcare.gov.

3. You'll be automatically re-enrolled if you bought on an exchange last year and do not renew coverage by today. If the health plan you signed up for is no longer offered, insurers can automatically enroll you in another policy similar to the one you have now. But you can opt out of any plan you’re automatically enrolled in and choose another up until Feb. 15.

4. Skip automatic enrollment and shop again, even if you liked your 2014 policy. The Department of Health and Human Services found that more than 70% of people who currently have insurance through the health law’s federal online marketplace could pay less for comparable coverage if they are willing to switch plans.

5. Costs have changed. Many plans will have out-of-pocket spending limits that are lower than the maximums allowed under the health law, according to an analysis by Avalere Health. But the tradeoff for those lower maximums may be a higher deductible, so be sure to pay attention to both figures when choosing your plan. You can also expect to see your premium change. Depending on where you live, that may be a good or bad thing. The premium for the second-lowest-cost silver plan in Nashville jumped 8.7%, while it dropped 15.6% in Denver, according to a study by the Kaiser Family Foundation.