Understanding Your Medicare Foundations

Turning 65 marks a significant milestone, often bringing with it a new set of health insurance decisions. For many Americans, Original Medicare (Parts A and B) forms the bedrock of their senior health coverage. But Original Medicare doesn't cover everything, leaving you exposed to potentially high out-of-pocket costs.

This is where Medicare Advantage and Medigap plans step in. Both are designed to fill those gaps, but they do so in fundamentally different ways. Making the right choice can save you thousands of dollars each year and ensure you get the care you need without financial stress.

What Original Medicare Covers – And What It Doesn't

Original Medicare includes Part A (Hospital Insurance) and Part B (Medical Insurance). Part A covers inpatient hospital stays, skilled nursing facility care, hospice, and some home health services. Most people don't pay a Part A premium if they've worked and paid Medicare taxes for at least 10 years.

Part B covers doctor visits, outpatient care, medical supplies, and preventive services. In 2026, the standard Part B premium is estimated around $190 per month, and you'll face a deductible, perhaps $260 annually. After meeting your deductible, Medicare typically pays 80% of approved costs, leaving you responsible for the remaining 20% coinsurance.

This 20% coinsurance has no annual limit under Original Medicare. A serious illness or extended hospital stay could quickly lead to medical bills reaching into the thousands. Original Medicare also does not cover prescription drugs (you need a separate Part D plan) or routine dental, vision, and hearing care.

Medicare Advantage (Part C): An All-in-One Alternative

Medicare Advantage plans, sometimes called Part C, are offered by private insurance companies like UnitedHealthcare, Humana, and Aetna. These plans contract with Medicare to provide your Part A and Part B benefits, often bundled with additional coverage.

Many Medicare Advantage plans include prescription drug coverage (Part D), along with benefits Original Medicare lacks. You might find plans that cover routine dental, vision, hearing, gym memberships, or even transportation to doctor appointments. Most plans have a $0 monthly premium beyond your standard Part B premium, making them attractive to many seniors.

However, Medicare Advantage plans usually operate within specific provider networks, like HMOs (Health Maintenance Organizations) or PPOs (Preferred Provider Organizations). With an HMO, you typically need a referral to see a specialist and must use in-network doctors. PPOs offer more flexibility but generally at a higher cost for out-of-network care.

These plans also have their own deductibles, copayments, and coinsurance for services. The good news is that all Medicare Advantage plans have an annual out-of-pocket maximum, which could be around $9,500 in 2026 for in-network services. Once you hit this limit, the plan pays 100% of your covered medical costs for the rest of the year.

Medigap (Medicare Supplement Insurance): Filling the Gaps

Medigap policies are also sold by private insurance companies, but they work differently. Instead of replacing Original Medicare, a Medigap plan works alongside it. It pays for some of the out-of-pocket costs that Original Medicare doesn't cover, such as your Part A and Part B deductibles, copayments, and coinsurance.

These plans are standardized across the country, meaning a Plan G from Aetna offers the exact same benefits as a Plan G from Blue Cross Blue Shield, though premiums will vary. With a Medigap plan, you can see any doctor or specialist in the US who accepts Medicare, without needing referrals or worrying about networks.

Medigap plans do not include prescription drug coverage, so you'll need to enroll in a separate Medicare Part D plan. They also don't typically offer extra benefits like dental, vision, or gym memberships. You'll pay a monthly premium for your Medigap policy, which is in addition to your Part B premium. These premiums can range from $120 to over $300 per month depending on the plan, your age, and your location.

One key advantage: once you enroll in a Medigap plan during your initial enrollment period, you generally cannot be denied coverage or charged more due to pre-existing conditions. This protection is especially valuable if your health changes later on.

Key Differences: Medicare Advantage vs. Medigap Plans

Deciding between these two options comes down to understanding their core distinctions. Here's a quick comparison of how they stack up on critical features:

This table highlights the trade-offs. Medicare Advantage offers bundled benefits and lower upfront premiums, but often with network restrictions. Medigap provides freedom of choice for doctors and predictable costs, but at a higher monthly premium and without extra benefits.

Cost Comparison: Premiums, Deductibles, and Out-of-Pocket Max

Let's look at how costs can vary for a senior in Phoenix, Arizona, in 2026. Remember, these are estimates, and actual costs depend on your specific plan and location.

Scenario 1: Medicare Advantage

You enroll in a UnitedHealthcare Medicare Advantage HMO plan. You still pay your $190/month Part B premium. Your MA plan premium is $0. You have a $0 deductible for doctor visits, but a $20 copay per visit. For a hospital stay, you might pay $300 per day for the first 5 days. Your annual out-of-pocket maximum is $8,800.

If you have a year with few medical needs, your costs are minimal – just your Part B premium and a few copays. If you have a serious illness requiring multiple hospital stays and specialist visits, you'll pay copays and coinsurance until you reach that $8,800 cap. Then your plan covers 100%.

Scenario 2: Medigap Plan G + Part D

You enroll in Original Medicare, a Humana Medigap Plan G, and a separate Aetna Part D plan. You pay your $190/month Part B premium. Your Medigap Plan G premium is $180/month. Your Part D premium is $35/month. Your total monthly premiums are $405 ($190 + $180 + $35).

With Plan G, you're responsible for the Part B deductible (around $260 in 2026). After that, Plan G pays your 20% Part B coinsurance. If you have a serious illness, your only out-of-pocket costs (beyond premiums and the Part B deductible) are for prescription drugs until you hit your Part D deductible and any coverage gap. Your total medical costs are highly predictable, but your monthly premium is higher upfront.

Choosing Your Carrier: UnitedHealthcare, Humana, and More

When you're ready to pick a plan, you'll choose from various private insurance companies. Major national carriers like UnitedHealthcare, Humana, Aetna, and Blue Cross Blue Shield offer both Medicare Advantage and Medigap plans. Kaiser Permanente is another significant player, especially on the West Coast, known for its integrated care model.

Each carrier might have different plan options, specific networks, and varied pricing for similar Medigap plans. For Medicare Advantage, plans can differ significantly in their extra benefits, copays, and drug formularies. It's crucial to compare plans from several carriers in your specific zip code. A good starting point is the official Medicare.gov plan finder tool.

Who Should Choose Which? Real-World Scenarios

The 'best' choice isn't universal; it depends entirely on your health, finances, and preferences.

• You're on a tight budget and generally healthy: Medicare Advantage might be a good fit. Many plans have $0 additional premiums beyond Part B, offering bundled benefits like dental and vision. You're comfortable using a network of doctors and appreciate the annual out-of-pocket maximum protection.

• You want maximum flexibility and predictable costs: Medigap, often Plan G or N, combined with a Part D plan, could be ideal. You're willing to pay a higher monthly premium for the freedom to see any Medicare-accepting doctor without referrals. You value knowing your medical costs (excluding prescriptions) will mostly be covered after meeting the Part B deductible.

• You travel frequently or live in multiple states: Medigap offers seamless coverage across the US with any Medicare provider. Medicare Advantage plans can be restrictive outside their service area, though most cover emergency care.

• You have chronic conditions and see many specialists: Medigap can simplify your care, as you won't need referrals or worry about network restrictions for each specialist visit. The higher premium can be offset by avoiding numerous copays and knowing your costs are capped (after the Part B deductible).

Consider your current doctors. If they're crucial to you, check if they accept the Medicare Advantage plan you're considering. With Medigap, as long as they accept Medicare, you're usually covered.

Making Your Decision for 2026

Choosing between Medicare Advantage and Medigap is one of the most important financial decisions seniors make. It impacts your access to care, your annual medical expenses, and your overall peace of mind. The Annual Enrollment Period from October 15 to December 7 is your primary window to make changes for the upcoming year.

Start by assessing your health status, anticipated medical needs, and financial situation. Do you value lower monthly premiums and extra benefits, or the freedom to choose any doctor and highly predictable costs? Don't hesitate to compare plans on Medicare.gov or consult with a licensed insurance broker. They can help you navigate the options available in your specific area and ensure you pick the right coverage for 2026.