If you are in the US, don't have employer-provided health insurance (hello layoffs, among others), and are thus buying your insurance on healthcare.gov or the state marketplaces, you might want to read siderea's series of posts on the subject soon: introduction, A health plan is a contract, and HSAs and bronze/catastrophic plans (so far). Technically you have until January 15 to sign up for 2026 insurance, but if you want insurance coverage in January, your deadline is Real Soon Now -- December 15 in most places, but earlier in some states. (I'm in PA where it's December 15; I haven't been tracking other places but Siderea mentions some in the introduction.)

Something I had missed is that for 2026, the government has admitted that bronze plans (with the lowest-but-still-high premiums) are inadequate, and you can now set up a Health Savings Account (HSA) with those plans. It's extra paperwork but can lead to savings on the money you were going to have to spend out of pocket anyway.