The government may automatically enroll you in Medicare if you’re already receiving Social Security or Railroad Retirement Board benefits within 4 months of your 65th birthday. You’ll also get auto-enrolled after 24 months of being on disability benefits.

You’re first eligible to enroll in Medicare 3 months before you turn 65. This initial enrollment period goes until 3 months after you turn 65. If you’re getting Medicare because of a disability, you can first enroll 3 months before your 25th month of disability payments.

You can enroll in three ways: Online through the Social Security Administration website (www.socialsecurity.gov), by calling 800-772-1213, or by visiting a local Social Security office in person.

Medicare provides answers to help you sign up for the plan that has the right coverage and cost for you. You can call 800-MEDICARE (800-633-4227) or visit Medicare.gov. State Health Insurance Assistance Programs (SHIPs) are paid for by the federal government and are free to use. They offer unbiased advice on your Medicare questions. Visit shiptacenter.org. Private insurance brokers who specialize in Medicare may be a resource as well.

After you’ve enrolled in Medicare, if you want to join, switch, or drop a plan, you need to do it during open enrollment, which is Oct. 15 to Dec. 7. If you’re enrolled in a Medicare Advantage plan, you can switch to a different Medicare Advantage plan or to Original Medicare from Jan. 1 to March 31 (one time).

Coverage begins the first day of your birth month, if you enroll during the 3 months before that month. If you enroll during your birth month or later, coverage begins the next month.

If you don’t sign up for Medicare during the initial enrollment period, you’ll be charged a fee on top of your monthly premium. This penalty fee will continue for as long as you have that type of coverage. Part A penalties only continue for twice the number of years you didn't sign up.

If you disagree with a penalty, you can request a review. Typically, this should be done within 60 days from the date on the penalty letter. This review is called an appeal.

Medicare works a little differently if you continue to work past age 65. When and what Medicare covers depends on the size of your employer, whether you get insurance from your employer, and whether you get a stipend from your employer for health insurance coverage.

You may feel as though you don’t need either Part A (hospital insurance) or Part B (medical insurance) of Medicare. You can either contact Social Security or send back your Medicare card from your welcome packet. Remember: For most people, Part A is free. Part B is not free, but if you drop it and then later change your mind, you will pay a penalty unless you are employed and have other insurance. Talk to a Medicare expert or SHIP before you drop Medicare, since there are consequences for doing so.