important medicare enrollment dates

if you snooze, you could lose premium dollars or coverage

When you're approaching the age of eligibility for enrollment in one of the many Medicare coverage plans, it's important to thoroughly research the benefits and costs of each plan, but it's probably even more important to make sure you enroll at the right time. Missing an enrollment date could cost you higher premiums down the line – or it could cost you coverage entirely.

if you're eligible for premium-free part A

If you're already receiving Social Security or Railroad Retirement Board benefits and you're a U.S. resident, you won't have to worry about your enrollment date, since the government automatically enrolls you in both Part A and Part B at age 65. (Three months prior to your 65th birthday, your Medicare card will arrive in the mail.)

Your only concern of timing would be if you declined Medicare Part B (and missed the initial enrollment window). If you do decline Part B, you will pay higher Part B premiums if you enroll later on. For each year that you don't enroll, your premium will be 10 percent higher, unless you're insured by your spouse's employer-sponsored health insurance.

if you aren't eligible for premium-free part A

If you are 65, but you're not receiving Social Security or railroad retirement benefits, you won't be automatically enrolled in Original Medicare. Instead, you'll be able to enroll during one of three enrollment periods.

• Initial Enrollment Period – a seven-month window of time that begins three months prior to the month of your 65th birthday. The date your Part B coverage starts depends upon how early in the IEP you enroll. If you wait until the last four months of the IEP, the start date of your coverage will be later.
• General Enrollment Period – January 1 to March 31 of each year. Your coverage will begin on July 1 of the year you enroll.
• Special Enrollment Period – You can wait to enroll in Part B and not incur a premium hike if you had coverage through your job or your spouse's job at the time you became eligible for Medicare. While you're still covered, you can enroll in Medicare at any time – and for another eight months after you lose your group coverage or you (or your spouse) stop working.

For more information about signing up in Parts A and B, call Social Security at 1-800-772-1213. (TTY users, call 1-800-325-0778.)

if you have end-stage renal disease

Individuals who have been diagnosed with end-stage renal disease (ERSD) – and who have had a kidney transplant or are undergoing dialysis– are eligible for Medicare. Your enrollment date in Medicare will depend on the date you begin receiving dialysis or the date you receive a transplant. You may also receive a combination of coordinated coverage from your employer – or COBRA – and Medicare.

Medicare has outlined a number of scenarios to guide you through various coverage options.

if you've been diagnosed with ALS

If you have been diagnosed with Amyotrophic Lateral Sclerosis (ALS), you'll be automatically enrolled in Medicare in the month you begin receiving Social Security Disability Insurance or a railroad disability annuity payment. Enrollees with ALS receive their Medicare Part A card through the mail the month their disability benefits begin.

when do I enroll in medicare advantage

If you want to enroll in a Medicare Advantage plan, you can do so when you're first eligible for Medicare or – if you have Social Security Disability Insurance, you can enroll in the 25th month of your disability or during the three months before or after that month.

You can also change to or from Medicare Advantage during Medicare's Open Enrollment period, which has changed. In 2011, it's from October 15 to December 7 and it continues from January 1 to February 14 in 2012. (Pay close attention to your options regarding Medicare Advantage changes, as they're not the same during both periods.) You may choose to:

• Change from Original Medicare to a Medicare Advantage plan – You can switch between October 15 and December 7, 2011.
• Change from a Medicare Advantage plan to Original Medicare – You can switch between October 15 and December 7, 2011 and also from January 1 to February 14, 2012. During the latter period, you also have the option of joining a Medicare Prescription Drug Plan.
• Switch from one Medicare Advantage plan to another – You can switch plans between October 15 and December 7, 2011.

when do I enroll in medicare part D?

With Medicare's prescription drug coverage, your first opportunity to enroll is when you're first eligible for Medicare (during the seven-month period beginning three months before your 65th birthday). If you enrolled in Medicare due to a disability, you can enroll during a six-month window beginning three months prior to your 25th month of disability.

It's important to note that if you don't enroll during the seven-month period when you're first eligible, you may pay a late-enrollment penalty (LDP) that will raise your Part D premium when you do decide to purchase coverage.

During the Open Enrollment Period mentioned above, you can also enroll in a Medicare Part D plan, switch to another Part D plan or leave Part D entirely. Again, pay close attention to the dates as they affect your options.

• Between October 15 and December 7, 2011 – You can join a Part D plan, switch between Part D plans or drop your Part D coverage.
• Between January 1 and February 14, 2012 – You can leave Original Medicare for an Advantage plan that offers prescription drug coverage. You can not switch from one Part D plan to another.

Still confused? Read this comprehensive guide to Medicare Enrollment Periods.

enrolling in medicare supplement insurance (medigap)

It's essential that you're conscious of your specified Medigap enrollment period, since it's the best time to enroll.

The enrollment period begins on the first day of the month in which both you and your spouse have reached the age of 65 and you have both enrolled in Medicare Part B. The period lasts for six months.

The timing for Medigap enrollment is pivotal. If enroll within the period, you can't be denied Medigap coverage or be charged more for the coverage because of a past medical condition. If you miss the enrollment period, your carrier has the option of denying the application based on the company's underwriting requirements.