Understanding how Medicare works before signing up can help you avoid errors like missing enrollment deadlines, overlooking costs, or choosing the wrong plans for your needs.

People who are ages 65 years or older, along with younger people who have certain disabilities or illnesses, can join Medicare. If you’re eligible because of a disability, you’ll receive automatic enrollment in Original Medicare. However, if you’re qualifying by age, you’ll need to sign up yourself.

It might seem easy just to pick the simplest Medicare plan, but taking the time to research and consider important factors can save you money and ensure you have the medical coverage you need.

Read on to learn about common mistakes people make when enrolling in Medicare and helpful tips on avoiding them.

When you become eligible, it’s really important to understand Medicare’s setup and the variety of plan options so you don’t end up with a plan that doesn’t fit your needs or costs too much.

Original Medicare consists of Part A, which covers hospital insurance, and Part B, which covers medical insurance. On the other hand, Medicare Advantage (Part C) is typically a private insurance plan that offers the same benefits and sometimes includes other benefits like dental, vision, or drug coverage.

You can also enroll in Part D for drug coverage, and if you need help with Original Medicare costs like deductibles and premiums, you may want to sign up for a Medicare supplement plan (Medigap).

Missing the right time to enroll in Medicare can lead to coverage gaps and unnecessary costs. For this reason, it’s a good idea to be aware of the different Medicare enrollment periods:

In addition, if you don’t qualify for premium-free Part A and don’t sign up on time, your premiums could go up by 10% for twice the number of years you didn’t have coverage.

For Part B, there’s a 10% premium increase for each year you delay signing up. And for Part D, Medicare will add a 1% penalty to your premium for each month you didn’t have coverage after 63 days.

Once enrolled in Medicare, there’s no need to sign up again each year if you’re happy with your current coverage. But it’s a good idea to review your coverage every year in case things change and you need something different.

With Part C specifically, insurers send out an Annual Notice of Change (ANOC), which explains any updates to costs and coverage starting in January.

It’s important to review this document. If you’re unhappy with the changes or need different coverage, you can switch Part C plans or return to Original Medicare.

Before signing up for Medicare, it’s helpful to understand the costs involved so you won’t be surprised.

In 2025, after paying a $257 deductible, Part B covers 80% of approved costs, with you covering the remaining 20%. The monthly premium for Part B starts at $185, though it might be higher depending on your income.

Part A usually doesn’t have a monthly fee but does have a $1,676 deductible. It fully covers the first 60 days of hospital stays and rehab, with some extra charges after that until day 101.

Parts C and D have varying premiums, deductibles, and coinsurance rates. Part D premiums may also be higher based on income, and drug copays depend on the formulary tier.

With Part C, you’ll still need to pay Part B premiums unless your Part C plan covers them. Medigap plans can help lower costs with Original Medicare, but these plans also come with their own premium.

There are several factors to consider when picking out Part C and Part D plans. First, you can check the available plans in your area on Medicare.gov, where you can also see how much the different plans cost and compare them.

It’s also important to ensure that Part D covers your prescription drugs and to check which tier they fall into. You should also consider the kind of Part C plan you want, as each type has its own considerations.

These include health maintenance organizations (HMOs), preferred provider organizations (PPOs), private-fee-for-service (PFF) plans, special needs plans (SNPs), and less common ones like point-of-service (HMO-POS) plans and Medicare Savings Programs (MSPs). Understanding these plans is crucial for finding the right fit.

Remember to check if you’re eligible for Medicare Savings Programs (MSPs) or programs like Extra Help and the Programs of All-Inclusive Care for the Elderly (PACE).

MSPs can help you with the costs of Part A and Part B premiums, deductibles, copays, and coinsurance. You’re eligible if your income and household resources do not exceed certain monthly limits.

The Extra Help program, also known as the Part D Low-Income Subsidy, offers financial assistance for prescription medications. Your income and financial needs determine your eligibility.

PACE delivers medical and social services to people with limited incomes who need home support. This program is a collaborative initiative between Medicare and Medicaid.

Some Part C plans, such as PPO plans, encourage you to use in-network providers. If you go out-of-network, you’ll have to pay more for medical care.

For this reason, it’s best to do this only if you have a specific specialist in mind who’s not part of the network. If you anticipate needing a particular specialist, it’s a good idea to pick an insurance plan that includes them.

Similarly, if you’re enrolled in Original Medicare, you may wish to consider whether to see a participating, non-participating, or opt-out provider, as this decision can also determine whether or not you’ll have additional costs.

It’s understandable if you confuse Medicare Advantage and Medigap, as they sound similar. But these are different plans that serve various purposes.

Medicare Advantage, or Part C, offers the same benefits as Original Medicare, giving you comprehensive medical coverage.

Meanwhile, Medigap is not medical insurance. This plan aims to help you with the out-of-pocket costs associated with Original Medicare, and it’s important to remember that you can’t use Medigap with Part C. There are different types of Medigap plans, so you’ll need to select the plan that best suits your needs.

If you sign up for a Medigap plan within 6 months of starting Medicare Part B, the insurer won’t be able to deny you coverage based on preexisting conditions. This means they won’t make you go through medical underwriting.

However, if you choose to enroll after this 6-month window, the insurer may deny you coverage. The only situations outside of the 6-month enrollment period when the insurer cannot deny you coverage are called guaranteed issue rights.

These are standard throughout the country, though some states may have longer guaranteed issue rights. Check the laws in your state to find out how this works in your area.

If you and your legal partner are both eligible for Medicare or if you’re eligible due to your spouse’s eligibility, there’s an important thing to keep in mind.

You’ll each need to choose your own Medicare plan and pay individual premiums for any plan you choose. This is significant in terms of planning costs and ensuring you each get coverage for the care you need.

For this reason, select the plan that suits you best rather than automatically signing up for your spouse’s chosen plan.

If you’re ages 65 or older or are younger and living with certain disabilities or conditions, you are eligible for Medicare. If you qualify due to a disability, you’ll receive automatic enrollment in Original Medicare. But if you’re signing up due to your age, you’ll need to register yourself.

Picking a Medicare plan might seem straightforward, but it’s important to do your homework and consider all the factors to prevent issues later. By familiarizing yourself with how Medicare operates, you can avoid common pitfalls like missing enrollment deadlines, underestimating costs, or selecting plans that might not be the best fit for you.