3 Things a 65-Year-Old Should Settle in October Before Medicare’s Dec. 7 Deadline
Three decisions stand between a new Medicare enrollee and costly mistakes, and one grows nearly impossible to reverse with every passing month. If you turned 65 this year, your window to act without consequences closes December 7.
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All premium, deductible and surcharge figures below come from the CMS fact sheet “2026 Medicare Parts A & B Premiums and Deductibles” and apply to the 2026 plan year.
If you turned 65 this year and picked Medicare coverage in a hurry, worry not: Open enrollment begins this week and runs from Oct. 15 to Dec. 7, with changes effective Jan. 1, 2027. Each decision below takes longer than expected, and one gets harder to reverse monthly.
An r/HealthInsurance thread shows the stakes: most states offer no guaranteed issue for a Medigap policy after time on an Advantage plan.
1. Lock In Your Structure While Medigap Insurers Must Say Yes
Your biggest choice is structural: Original Medicare plus a Medigap supplement, or an all-in-one Medicare Advantage plan. Moving from one to the other is far easier in one direction than the other.
Federal law gives people 65 or older a one-time, six-month opportunity after Part B starts to buy any Medigap plan without medical underwriting. Once that window closes, insurers can generally refuse coverage to applicants whose medical history or current health problems might make them expensive to cover. The December 7 deadline lets you drop Advantage and return to Original Medicare, yet a Medigap insurer can still review your health and deny you.
Original Medicare without a supplement has no annual out-of-pocket cap. In 2026, a hospital admission costs $1,736 per benefit period, and days 61 through 90 cost $434 per day. Medigap absorbs those hits. Advantage plans trade them for provider networks and prior authorization.
New 65-year-olds get one escape hatch. If you joined an Advantage plan when first eligible, a “trial right” lets you switch to original Medicare within the first year and buy a Medigap plan too. If you live in Connecticut, Massachusetts, or New York, you can buy Medigap anytime without underwriting. Everyone else gets one clean shot.
2. Find Your IRMAA Tier Before Social Security Does
Only roughly 8% of Part B enrollees pay the income-related monthly adjustment amount (IRMAA). New retirees face the most risk, because Social Security relies on the most recent federal tax return the IRS provides, which often reflects a full year of salary. Social Security measures MAGI as total adjusted gross income and tax-exempt interest income, so municipal bond interest counts.
| Single MAGI | Joint MAGI | Part B total premium (monthly, per person) | Part D surcharge (monthly, per person) |
|---|---|---|---|
| $109,000 or less | $218,000 or less | $202.90 | $0.00 |
| Over $109,000 to $137,000 | Over $218,000 to $274,000 | $284.10 | $14.50 |
| Over $137,000 to $171,000 | Over $274,000 to $342,000 | $405.80 | $37.50 |
| Over $171,000 to $205,000 | Over $342,000 to $410,000 | $527.50 | $60.40 |
| Over $205,000 and under $500,000 | Over $410,000 and under $750,000 | $649.20 | $83.30 |
| $500,000 or more | $750,000 or more | $689.90 | $91.00 |
If your income fell because you stopped working, file Form SSA-44. Social Security accepts requests to lower IRMAA after life-changing events such as marriage, divorce, the death of a spouse, loss of income, and an employer settlement payment. A voluntary Roth conversion or home sale stays on the books.
CMS released 2026 figures on November 14, 2025. Budget with the 2026 table until 2027 figures arrive. The Part B premium comes straight from your Social Security check, and the 2027 cost-of-living adjustment is tracking toward 3.3%. IRMAA is only one of several surcharges that quietly inflate the Medicare bill, and we mapped the rest in a free guide to Medicare’s hidden costs.
3. Price Your Drugs and Confirm Your Doctors by Name
Plans sent Annual Notices of Change by Sept. 30. If you do nothing, your plan renews with every formulary, pharmacy and premium change in place. Enter each prescription, dose and pharmacy into Medicare’s Plan Finder and compare total yearly cost. “Don’t assume a plan that worked well in 2026 will remain your best option,” said Ryan Ramsey of the National Council on Aging.
Call each doctor’s billing office to confirm network status for your specific plan in 2027. Networks shift fast: An estimated 1 in 10 Advantage members were forced out of their plans this year after insurers pulled out of markets.
Settle the Structure Before Anything Else
If you are still inside your six-month Medigap window or your first-year trial right, choose Original Medicare with a Medigap plan, unless you live in a state with year-round guaranteed issue. A $0-premium Advantage plan saves money in healthy years. Your guaranteed right to buy Medigap is far harder to replace.
- Find your Part B start date on your Medicare card. Your Medigap window runs six months from that date.
- Pull your most recent Form 1040, add line 11 to line 2a and compare the result to the table above.
- Finish your plan comparisons by Halloween so a network or formulary surprise leaves you time to act before Dec. 7.
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Joel South covers large-cap stocks, dividend investing, and major market trends, with a focus on earnings analysis, valuation, and turning complex data into actionable insights for investors.
He brings more than 15 years of experience as an investor and financial journalist, including 12 years at The Motley Fool, where he served as an investment analyst, Bureau Chief, and later led the Fool.com investing news desk. He has also co-hosted an investing podcast and appeared across TV and radio discussing market trends.
