If you miss your enrollment period, you can pay a fee for late enrollment which can vary from state to state. However, you do not have to do so when applying during a special enrollment period. A special enrollment period is a period in which someone can enroll in coverage outside the general enrollment window due to a specific qualifying event. 

Qualifying events are extraneous circumstances that are particularly beyond the scope of control.  For example, you are allowed to apply for coverage without a fee if your employer stops providing coverage suddenly or your previous medical health provider randomly closes their doors for business. Otherwise, your best option is to wait for a general enrollment period and go that route. In the long run it is less of a hassle to enroll during the general enrollment window.

General enrollment periods vary by coverage type. Medicare Part A will have a different enrollment period from Part D.  So be aware of your enrollment period for your specific coverage type to avoid enrolling in a coverage plan late, which can lead to a loss of coverage or interrupted coverage. If you are enrolling in Medicare Part A or Medicare Part B, open enrollment occurs in the early part of the calendar year. 

It begins on January 1 and ends on March 31 each year. The Medicare Advantage Plan, which is also known as Medicare Part C, begins open enrollment annually on October 15, and enrollment closes on December 7. Medicare Part D enrollment also occurs during that enrollment period. Medicare Part C provides coverage through Medicare-approved private companies. Medicare Part D provides prescription drug coverage.

A final thing to note about qualifying for Medicare is it is possible to qualify for different types of Medicare coverage at different times. This can help decide on what plan you specifically need versus one that you are forced into having.  For instance, you may apply for Part A coverage when you reach 65 years of age. If you are still employed at that time, you may not require Medicare Part B due to being employed. However, you may qualify for additional Part B coverage after retirement. Checking in with your Medicare plan a few times throughout the enrollment and after will help you understand exactly what plans you are able to qualify for.