If you're turning 65 this year, you're about to face a decision that could swing your household budget by $5,000 or more annually.
The choice between Medicare Advantage and a Medicare Supplement plan isn't just a coverage question—it's a cash flow question that plays out every single month.
Both paths start at the same place: you enroll in Original Medicare, which covers hospital stays (Part A) and doctor visits (Part B).
The standard Part B premium runs $185 monthly in 2025, deducted straight from your Social Security check.
What happens next is where the two options split hard.
Medicare Advantage, also called Part C, replaces Original Medicare with a private insurer's network plan.
The pitch is appealing: many carry $0 premiums, and most include prescription drug coverage plus extras like dental, vision, and gym memberships.
Nearly 33 million Americans—more than half of all eligible beneficiaries—have chosen this route, according to KFF.
Advantage plans cap your annual out-of-pocket costs, but those caps can reach $9,350 for in-network care in 2025 and higher for out-of-network.
Every specialist visit, imaging test, or hospital stay chips away at that limit.
You also stay inside a network, and referrals often require a primary care gatekeeper.
You keep Original Medicare and add a supplement policy that picks up most of what Medicare doesn't pay.
A Plan G policy, the most popular option for new enrollees, covers nearly everything except the $283 Part B deductible.
You can see any provider in the country who accepts Medicare—roughly 99% of physicians.
A Medigap Plan G for a 65-year-old can run $130 to $200 monthly depending on your state and gender, and those premiums typically climb with age.
Add a standalone Part D drug plan at $40 or so, and you're looking at $350 to $450 monthly before you see a single doctor.
A healthy 65-year-old on Advantage might pay $0 premiums and maybe $500 in copays all year.
The same person on Medigap pays $4,000 to $5,000 in premiums whether they use care or not.
But let one serious diagnosis hit—cancer, a joint replacement, a cardiac event—and Advantage copays can stack to $6,000 or more, while Medigap keeps you near the deductible.
First, Medigap insurers in most states can reject you or charge more based on health history after your initial six-month enrollment window closes.
Miss it, and you may never qualify affordably again.
Second, Advantage plans can change their networks, formularies, and copays every January—what looks cheap today may not in three years.
Consumer advocates also flag a marketing problem.
A 2023 Senate report found some Advantage call centers used aggressive tactics, and federal regulators have tightened rules on television ads that promise "extra benefits" without explaining network limits.
If you travel, want zero referrals, or have any chronic condition, Medigap's predictability often justifies the premium.
If you're healthy, budget-conscious, and comfortable inside a network, Advantage can free up real money each month—as long as you bank the difference against a bad year.
My take: treat this as a healthcare budget decision, not a shopping bargain.
Final Thoughts
Run your actual prescriptions and doctors through both plans before enrolling, and remember that the cheapest monthly premium can become the most expensive choice the moment your health changes.