How to avoid Medicare Part B late enrollment penalties Planning to retire soon? Here’s what to know about timing your Medicare enrollment to steer clear of costly penalties. Federal annuitants enrolling in Medicare Part B face many healthcare expenses: FEHB and Part B premiums, potential Part B and Part D Income Related Monthly Adjustment Amounts (IRMAA), and out-of-pocket costs when using healthcare services. One expense you’ll want to avoid is the Part B late-enrollment penalty. I’ll ...