Late enrollment penalties may apply if you delay Medicare without qualifying coverage.Part B: The penalty is generally 10% for each full 12-month period you could have had Part B but did not enroll.Part D: The penalty is generally 1% for each month you went without Part D or other creditable drug coverage after becoming eligible.Part A: A penalty may apply if you must pay a premium for Part A and delay enrollment.These penalties may continue for as long as you have that type of Medicare coverage.