Health Insurance Mistakes That Cost You Money

The most costly health insurance mistakes are picking a plan by premium alone and skipping the network and drug checks. Others include renewing on old income and missing tax steps after you enroll. Each one can add thousands of dollars to your year. The good news is that each one takes only a few minutes to avoid.

Why health insurance mistakes cost so much

Health coverage has a lot of moving parts. You pay a premium every month, and then you share costs when you get care. On top of that, your tax credit depends on an income guess. So a small slip in any one area can ripple through your whole year.

Also, the stakes went up recently. The extra COVID-era tax credits ended after 2025, and deductibles climbed. As a result, the cost of a wrong choice is higher than it was a few years ago. Below are the health insurance mistakes we see most, grouped by when they happen.

Buying mistakes that raise your total cost

Most buying mistakes come from looking at one number instead of the whole picture. Here are the four we hear about most on the phones.

1. Shopping by premium alone

A cheap premium feels like a win. However, it often comes with a high deductible, which is what you pay before the plan shares costs. Say a plan saves you $100 a month but has a deductible $4,000 higher. In a year with a surgery, you could lose $2,800 on that trade. So compare premiums plus likely care costs.

2. Skipping the network check

Every plan has its own network of doctors and hospitals. Even plans from the same insurer can use different networks. So a doctor who took your old plan may not take your new one. Use our carrier directory search links, and then call the office to confirm.

3. Ignoring the drug list

The same drug can sit on a different tier in each plan. For example, one plan may charge a flat copay while another charges coinsurance after the deductible. So look up every drug you take before you enroll.

4. Mixing up the deductible and the maximum

The deductible is where cost sharing starts. The out-of-pocket maximum, by contrast, is where it stops for covered in-network care. For 2027, that cap can reach $12,000 for one person. Our guide to what counts toward your deductible explains both.

Renewal mistakes that sneak up on you

Renewal mistakes are sneaky, because doing nothing feels safe. In fact, it's often the costliest choice.

5. Letting auto re-enrollment decide

If you don't act by December 15, HealthCare.gov re-enrolls you in the same plan or a similar one. That keeps you covered. Still, it doesn't check your doctors, your drugs or your new price. Our guide on what happens when your plan renews lists every step.

6. Using last year's income

Your tax credit depends on what you expect to earn next year. So if you got a raise, started a business or lost a job, update the number. Otherwise, your credit may be too high, and you'll owe the extra back at tax time.

7. Missing the first payment

When you switch plans, coverage generally won't start until you pay the first premium. You pay the new insurer directly, not the Marketplace. So set up autopay the day you enroll.

• Waiting until January 15 and getting a February 1 start
• Assuming your doctor stayed in network
• Skipping the renewal letters from your insurer and the Marketplace

Your next step: run our yearly coverage checkup checklist before you renew.

Tax and enrollment mistakes after you sign up

Many people think the work ends once they pick a plan. However, tax credits come with paperwork, and mistakes here can show up as a bill in April.

8. Skipping Form 8962

If you got advance credits, you must file Form 8962 with your tax return. That's true even if you wouldn't otherwise need to file. If you skip it, you can lose your credits in future years. Then you'd pay the full premium.

9. Not reporting changes mid-year

Report income and household changes to the Marketplace as soon as they happen. For instance, a new job, a marriage or a big contract can all change your credit. Since tax year 2026, there's no cap on repaying extra credits. So a quick update beats a surprise tax bill.

Health insurance mistakes about plan type

Some health insurance mistakes aren't about price at all. Instead, they come from buying a plan type that doesn't match your needs.

10. Treating a short-term plan like ACA coverage

Short-term plans can cost less and can help healthy people bridge a gap in approved states. Even so, they work very differently from Marketplace plans.

Where they're sold, you can compare short-term plans in approved states with an agent who explains the limits.

11. Staying with a carrier that's leaving

For 2027, Cigna is leaving the individual market in all 11 states where it sold plans. Molina is also leaving Florida's individual Marketplace. If you're a member of either, don't wait for the Marketplace to match you. Instead, pick a new plan by December 15, so your doctors stay in network on January 1.

How to avoid health insurance mistakes in five steps

You don't need to be an expert. You just need the same short routine every fall. First, gather your renewal letters, a pay stub and a list of your doctors and drugs.

1. List your care

   Write down every doctor, drug and expected visit for next year.

2. Estimate income

   Use next year's expected household income, not last year's.

3. Compare total cost

   Add 12 months of premiums to the care you expect.

4. Confirm networks and drugs

   Check next year's directory and drug list for each plan.

5. Enroll early and pay

   Pick by December 15, then set up autopay.

Price the whole year, not the monthly bill.The habit that prevents most costly errors

If something already went wrong, see our guide to fixing denied claims and billing errors. To learn how a broker helps, read why people use a licensed agent. Then compare ACA and private plans in your ZIP code, or call 888-730-6031.

Health insurance mistakes: FAQs

Want more answers? Browse our library of health plan questions, or see the key dates for this enrollment season.

Sources

• KFF: The average Marketplace deductible grew by about $1,000 per person in 2026
• CMS: 2027 Payment Notice parameters guidance
• IRS: Questions and answers on the Premium Tax Credit
• HealthCare.gov: Federal poverty level (FPL)
• HealthCare.gov: Keep or change your insurance plan
• KFF: Tracking insurer participation changes in the ACA Marketplaces in 2027

Vivna Insurance is a licensed, independent health insurance agency (NPN 19168641). We are not affiliated with HealthCare.gov or any government agency. Plan availability, networks and benefits vary by state and change over time. Short-term plans are available only in approved states and are not ACA-compliant coverage.

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