With open enrollment season here, millions of Americans have until January 15 to choose a new health plan, opt out of an existing one, or switch between options.

However, for coverage starting Jan. 1, the deadline to enroll is Dec. 15. Anyone signing up later will not be covered by their new policy until February.

But choosing a plan can be tricky, given the multitude of factors that can have a financial impact on buyers. People are usually tied to their health insurance for a year without exception, so it's vital to weigh options and terms before making a decision.

"It is confusing, and people have no idea how much they could potentially have to pay," Carolyn McClanahan, a medical doctor who is also a certified financial planner and founder of Life Planning Partners, based in Jacksonville, Florida, told CNBC.

When considering health insurance plans, here's what to keep in mind:

  • Coverage In 2023 will Like Cost More Upfront: According to Cynthia Cox, director of the Kaiser Family Foundation's Affordable Care Act program, premiums are rising 4 or 5% on average.
  • The Average Cost Of Premiums: Per a recent Kaiser Family Foundation report, the average cost is around $7,911 for individuals and $22,463 for families.
  • Subsidies Can Help You Save: The Biden administration in August extended subsidies through 2025 that can help people save on insurance, partly based on income, among other factors.
  • Open Marketplace Options: Workers without "affordable" employer-sponsored health insurance—representing 9.61% of income in 2022—are able to obtain a plan through the open marketplace. However, these arrangements might mean families being split between plans, ultimately driving up medical bills for some households.
  • "In-Network" Providers: Medical costs vary based on the insurer's network, with "In-network" providers usually costing significantly less than "out-of-network" providers.