The deadline to shop for a health insurance plan on the federal marketplace is here, and so far more than 579,000 Texans have purchased insurance on healthcare.gov.

While that’s nearly 30 percent higher than the sign-up rate this time last year, one reason the pace might be accelerated is because the period to enroll in 2018 plans is 45 days shorter this year.

Most Texans have until Friday to shop on the federal marketplaces established by the Affordable Care Act. Indeed, despite a tumultuous year of back-and-forth debate and various failed attempts by Republicans to repeal or replace the Obama-era health law, it remains in effect.

Health insurance experts are urging those who still need to make selections to not just let an existing plan simply expire. Options that were available this year may not be sold for 2018, and people enrolled in those expired plans will be automatically put into a new option that they did not actively select. And there’s good reason to shop around, experts say.

Of the 10.7 million Americans who are uninsured and eligible to purchase marketplace plans, an estimated 4.5 million qualify for a zero-cost monthly premium bronze plan, according to the Kaiser Family Foundation. The subsidies that they would qualify to receive essentially offset the costs.

The subsidies to reduce monthly premiums remain in place for people up to 400 percent of the federal poverty level. To put it in context, that's a salary range between $12,060 and $48,240 for a single person, and an salary range between $24,600 and $98,400 for a family of four.

An estimated 1.4 million people can get a bronze plan with a premium that’s lower than the penalty they’d pay (for not buying insurance) when they file their 2018 taxes. That penalty is $695 per adult in a family, $347.50 per child under 18, or up to 2.5 percent of the family income.

However, there are downsides. “I get nervous about promoting the zero-dollar premiums,” admitted Stacey Pogue, senior policy analyst with the Center for Public Policy Priorities.

“Not because it's not true. ... It's just that those bronze plans can have $7,000 deductibles.”

For people who fall under 250 percent of the poverty line, the better value, she says, is often silver plans, which have higher monthly rates but lower annual deductibles, she says.

And those who do not qualify for federal subsidies will feel the brunt of the price increases.

Some Texans who miss the the Friday deadline may have a little more time to mull over the options. People living in 53 Texas counties identified by the Federal Emergency Management Agency after hurricanes devastated the state this summer will qualify for a special enrollment period that runs through Dec. 31.

The list mainly includes hard-hit counties in southeast Texas, but Dallas and Tarrant are also included because of the public assistance offered and relocation of evacuees. Though analysts suggest not using the opportunity if you don’t absolutely have to.

The special enrollment between Saturday and the end of the month will be more complex, Pogue warned. For one, a phone call will be required to approve the special enrollment period and the wait times are expected to be long. And it could get tricky for individuals already in an ACA- qualified health plan who end up getting auto-enrolled into a new one that starts in January.