Choosing not to enroll in Medicare Drug coverage when you are first eligible could lead to a late enrollment penalty. The penalty does not apply if you had other creditable drug coverage (such as employer/union coverage, VA benefits) or if you get Extra Help.
The late enrollment penalty is 1% of the average cost of a Medicare Part D plan. That average for 2020 is about $32.74, which would be around $.30. That small penalty accumulates for the number of months you go without drug coverage. Once you do enroll in a drug plan, that extra penalty is added on to your monthly cost. For example, if you go two years without drug coverage and then enroll in a plan, Medicare would add on about $7.20 a month to the cost of your drug plan.