If you need to buy health insurance, don't procrastinate. Pablo Martinez Monsivais/AP hide caption
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Major changes to individual health coverage provided through the Obamacare marketplaces won't happen overnight. PhotoAlto/Frederic Cirou/Getty Images hide caption
Alina Nurieva (right) sat with Gabriela Cisneros, an insurance agent from Sunshine Life and Health Advisors, and picked an insurance plan at the Mall of the Americas in Miami last November. Joe Raedle/Getty Images hide caption
Mark Bertolini, CEO of Aetna, told the Justice Department in July that the insurer would walk away from many health exchanges if the government opposed the company's proposed deal for Humana. On Tuesday, Aetna followed through. Andrew Harrer/Bloomberg via Getty Images hide caption
Aetna is the latest big health insurer to retreat from the exchanges established under the Affordable Care Act. Jessica Hill/AP hide caption
At Blue Cross and Blue Shield headquarters in Eagan, Minn., the losses on the sale of insurance plans to individuals led to a change in course. Jim Mone/AP hide caption
When deductibles and copays are high, quite a few people with insurance turn to free clinics for care. Jens Magnusson/Ikon Images/Getty Images hide caption
People with diabetes who sign up for an Aetna insurance plan focused on diabetes care can get blood sugar meters and test strips free of charge. iStockphoto hide caption
Geisinger Health System, based in Danville, Pa., offers both insurance and patient care. Bradley C. Bower/Reuters/Landov hide caption
Even people who buy high-deductible health plans can get coverage of many preventive services without any out-of-pocket costs. /iStockphoto hide caption
HealthCare.gov plans for 2016 open for enrollment on Sunday. Meredith Rizzo/NPR hide caption
Secretary of Health and Human Services Sylvia Burwell talks before a Capitol Hill hearing Wednesday with Rep. Paul Ryan, R-Wis., as Rep. Pat Meehan, R-Pa., looks on. Getty Images hide caption
People protesting against the Affordable Care Act rallied outside the Supreme Court in March, before arguments in the second major challenge to the law. Jim Lo Scalzo/EPA/Landov hide caption