People whose jobs don't offer health benefits, self-employed entrepreneurs and young adults are among the Illinois residents who will start shopping for health coverage this weekend. Saturday is the first day of the second sign-up season under the nation's year-old health system.

Here are five things to know about open enrollment for 2015 insurance coverage under the Affordable Care Act:

1. SHORTER SEASON

Starting Saturday and ending Feb. 15, it's a shorter enrollment period compared to last year. Plus, it coincides with the holiday season, which may distract some people from taking the time they need to make complicated insurance decisions.

2. COSTS RISING

Financial help is available on a sliding scale, depending on income. In Illinois, insurance prices are up slightly, on average, for the lowest cost "silver" plans — the most popular policies on the marketplace. Prices vary across the state, so consumers should carefully compare what's available in their area. People whose financial information has changed should update their accounts on HealthCare.gov to make sure they get the correct amount of help.

3. TAX PENALTIES FOR GOING WITHOUT INSURANCE

The health law requires most people to have health insurance. The penalty for having no health insurance in 2015 is going up to $325 per adult or 2 percent of household income, whichever is greater, up to a cap.

4. MORE CHOICES

There are more insurance companies selling plans on the Illinois marketplace this year and more plans from which to choose. All counties in Illinois have a minimum of 56 plans available, including some designed for small businesses. Some have optional benefits such as adult dental and vision coverage.

5. DEADLINES

For coverage to start on Jan. 1, people need to sign up by Dec. 15. Those already enrolled in a health plan who want to switch to a different one also need to do so by Dec. 15 to avoid automatic re-enrollment in their existing plan. To avoid a tax penalty for remaining uninsured, consumers need to sign up by Feb. 15.