Understanding Medicare: A Timeline for New Jersey Residents Approaching 65

Medicare is one of the most significant transitions in retirement, and one of the most confusing. The enrollment windows are strict, the penalty for missing them can follow you permanently, and the way Medicare interacts with your retirement income plan is more complex than most people expect. This guide is designed to walk New Jersey residents through the timeline, explain what each part of Medicare covers, and highlight the financial planning considerations that are easy to overlook.

What the Parts of Medicare Cover

Medicare is divided into four parts, each covering different types of healthcare:

Medicare Part A (Hospital Insurance)

Covers inpatient hospital stays, skilled nursing facility care (limited), hospice care, and some home health services. Most people pay no monthly premium for Part A if they (or a spouse) paid Medicare taxes for at least 10 years (40 quarters).

Medicare Part B (Medical Insurance)

Covers doctor visits, outpatient services, preventive care, durable medical equipment, and some home health services. Part B requires a monthly premium that is income-adjusted (more on this below). The standard Part B premium for 2026 is set annually by CMS, and higher-income enrollees pay more through IRMAA surcharges.

Medicare Part C (Medicare Advantage)

Medicare Advantage plans are offered by private insurance companies approved by Medicare. They bundle Part A and Part B coverage and often include Part D (prescription drugs), plus additional benefits like dental, vision, and hearing. You must be enrolled in Part A and Part B to join a Medicare Advantage plan. Costs, networks, and coverage vary by plan and by region. New Jersey has a range of Medicare Advantage options, though availability depends on the county.

Medicare Part D (Prescription Drug Coverage)

Part D covers prescription medications. It is offered through private insurers and has its own monthly premium, deductible, and formulary (list of covered drugs). If you do not enroll in Part D when you are first eligible and do not have other creditable drug coverage, you may owe a permanent late enrollment penalty.

The Medicare Enrollment Timeline

Understanding the enrollment windows is critical because missing them can result in penalties that last for the rest of your life.

Initial Enrollment Period (IEP)

Your Initial Enrollment Period is a 7-month window: the 3 months before your 65th birthday month, your birthday month itself, and the 3 months after. If you are not covered by an employer group health plan (or your spouse’s), you should enroll during this window to avoid late penalties. If you are already receiving Social Security benefits, you will be enrolled in Part A and Part B automatically.

Special Enrollment Period (SEP)

If you are still working at age 65 and covered by an employer group health plan (with 20 or more employees), you can delay Medicare Part B without penalty. Once you leave the job or lose the employer coverage, you have an 8-month Special Enrollment Period to sign up for Part B. This is important: COBRA and marketplace plans do not count as employer group coverage for this purpose. If you retire and go on COBRA, your SEP clock starts when your employer coverage ends, not when COBRA ends.

General Enrollment Period (GEP)

If you missed your IEP and do not qualify for a SEP, you can enroll during the General Enrollment Period, which runs from January 1 to March 31 each year. Coverage begins July 1. Late enrollment penalties will apply.

Annual Open Enrollment (October 15 to December 7)

This is the annual window to change your Medicare Advantage plan, switch from Medicare Advantage back to Original Medicare, or change your Part D plan. This is not the time to enroll in Medicare for the first time.

Late Enrollment Penalties

Missing your enrollment window does not just delay your coverage. It increases your premiums permanently.

• Part B penalty: Your premium increases by 10% for every full 12-month period you were eligible but did not enroll. This penalty is added to your monthly premium for as long as you have Part B. If you delayed enrollment by 3 years, you would pay a 30% higher premium every month for life.
• Part D penalty: The Part D late enrollment penalty is calculated based on the number of months you went without creditable drug coverage. It is added to your monthly Part D premium permanently. Like Part B, this penalty does not go away.

These penalties are one reason why Medicare enrollment timing should be part of your retirement planning well before you turn 65.

Medigap (Medicare Supplement) Plans

If you choose Original Medicare (Part A and Part B) rather than Medicare Advantage, you may want to add a Medigap plan. Medigap plans are sold by private insurers and cover some of the costs that Original Medicare does not, including copayments, coinsurance, and deductibles.

In New Jersey, Medigap plans have some unique features. New Jersey is one of a small number of states that requires Medigap insurers to offer open enrollment to beneficiaries at any time, not just during the initial 6-month Medigap open enrollment period. This is a meaningful consumer protection that gives NJ residents more flexibility to switch plans later without medical underwriting.

Medigap plans are standardized by letter (Plan A, Plan F, Plan G, Plan N, etc.), so the benefits for a given plan letter are the same regardless of the insurance company selling it. The price, however, can vary significantly between insurers. Comparing premiums for the same plan letter across carriers is worth doing.

IRMAA: The Medicare Surcharge That Catches People Off Guard

IRMAA (Income-Related Monthly Adjustment Amount) is a surcharge added to your Medicare Part B and Part D premiums if your income exceeds a threshold. The key detail that surprises many people: IRMAA is based on your modified adjusted gross income (MAGI) from two years prior. Your 2026 income determines your 2028 Medicare premiums.

This two-year lookback creates an important planning consideration. A large Roth conversion, the sale of a property, or a significant capital gain in one year can push your income above an IRMAA threshold two years later, adding hundreds or even thousands of dollars in annual Medicare premiums. The surcharge applies per person, so a married couple can be affected twice.

If you experience a life-changing event (retirement, loss of income, death of a spouse, divorce), you can request that Social Security use a more recent year’s income instead of the two-year lookback. This is done through a Medicare IRMAA Life-Changing Event form (SSA-44).

Bridging the Gap: Healthcare Before 65

If you retire before age 65, healthcare coverage becomes one of the most important logistical and financial questions to address. Your options include:

• Spouse’s employer plan: If your spouse is still working and has employer coverage, this is often the most straightforward and cost-effective option.
• COBRA: You can continue your former employer’s group plan for up to 18 months, but you pay the full premium plus a 2% administrative fee. COBRA premiums can be substantial, often $1,500 to $2,500 per month for a couple.
• ACA marketplace plans: New Jersey operates its own health insurance marketplace (GetCovered.NJ.gov). Premium subsidies are available based on your modified adjusted gross income, which means controlling your income in early retirement (through careful withdrawal and Roth conversion planning) can reduce your marketplace premiums significantly.

The cost of pre-65 healthcare should be factored into any early retirement plan. It is one of the expenses that can make the difference between retiring at 60 and waiting until 65.

How Medicare Fits Into Your Retirement Income Plan

Medicare is not just a healthcare decision. It is a financial planning decision that intersects with your income strategy, your tax planning, and your long-term withdrawal plan:

• Income management: Keeping income below IRMAA thresholds can save thousands in Medicare premiums. This affects decisions about Roth conversions, capital gains harvesting, and the timing of retirement account withdrawals.
• NJ pension exclusion interaction: For NJ residents 62 and older, the pension exclusion threshold ($150,000) and IRMAA thresholds create two separate income ceilings to manage. The NJ Retirement Tax Guide covers the pension exclusion rules in detail.
• Roth conversion timing: Converting before Medicare enrollment (or strategically sizing conversions to stay below IRMAA thresholds) can reduce lifetime Medicare costs. The Roth Conversion guide covers this trade-off.
• Social Security timing: When you claim Social Security affects your income, which affects your IRMAA bracket, which affects your Medicare costs. These decisions are interconnected.

Planning for Medicare Should Start Before 65

The team at GPS Wealth Management in Marlton, New Jersey, helps clients approaching retirement understand how Medicare fits into their broader financial plan. The enrollment timeline, the premium structure, and the way Medicare costs interact with your income and tax strategy are all things worth planning for in advance, not figuring out on the fly.

The team at GPS Wealth Management offers retirement planning, tax planning strategies, and financial planning for individuals and families across South Jersey. Contact us or call 856-552-0746.