Part D is an elective benefit. It does not come included with Original Medicare and Medigap. Those on the Medicare Advantage Plan (Part C) do not need Part D because their plan includes prescription drug coverage.

People who want to enroll in Part D will want to do it when first eligible otherwise they may pay a late enrollment penalty. It is possible they’ll pay this penalty for as long as they have the Part D coverage.

Before opting for Part D, people need to review any other drug coverage they may have. This could be from an employer, the Department of Veterans Affair, TRICARE, union, or a Medigap policy. Medicare.gov describes how Part D works with other insurance.

Many factors affect the cost of any prescription. The plan requires paying a monthly premium, a yearly deductible, copayments, and any unique costs such as coverage gap, late enrollment, or Extra Help (Medicare program for those with limited resources and income).

As for the cost of premiums, it also depends on different variables including income and type of tax return filing. The yearly deductible for drug plans is the amount a person pays for prescriptions before the Medicare Prescription Drug Plan pays its part. Deductibles vary based on drug plans. In fact, some may not have a yearly deductible.

Drug plans with a copayment require you to pay a flat fee for a drug depending on its tier. Brand-name prescriptions tend to have a higher fee than generics. Coinsurance involves paying a percentage of the cost of the drug.

Those who enroll in Part D after the enrollment period ends pay a penalty. That penalty depends on how long they went without prescription drug coverage and the national base beneficiary premium. Ideally, people will want to enroll in Medicare plans during the eligibility period to avoid extra fees.