Turning 65 comes with a lot of to-do items. But one of the most important (and easiest to miss) is signing up for Medicare on time. Getting it wrong doesn’t just delay your coverage. It can lock in higher premiums for the rest of your life.
Here’s what you need to know before that birthday arrives.
Your Enrollment Window Is Shorter Than You Think
Medicare gives you a seven-month window to sign up. It opens three months before the month you turn 65 and closes three months after. Miss that window without a good reason, and the penalties kick in.

Most people don’t pay a monthly premium for Medicare Part A, which covers hospital care. But Part B (which covers outpatient care like doctor visits) does come with a monthly premium. Sign up late, and you face a 10% surcharge on that Part B premium for every 12-month period you were eligible but didn’t enroll.
That surcharge doesn’t go away. It follows you for life.
Part D Has a Penalty Too
Prescription drug coverage under Medicare Part D has its own deadline. If you go more than 63 days without what’s called creditable drug coverage, you’ll face surcharges on your Part D plan premiums as well. Those costs can really add up over the years.
Still Working at 65? You May Be Able to Wait

If you’re still on the job at 65 and covered through your employer, you may be able to delay Medicare without penalty. This is called a special enrollment period.
But there’s a catch. That protection typically only applies if your workplace health plan covers 20 or more employees. If your employer’s plan is smaller than that, you don’t qualify, and you need to sign up for Medicare during your initial window.
If you do qualify for a special enrollment period and miss the initial window, you can still sign up later without facing the lifetime penalties, as long as you enroll before that special period closes.
Why This Matters for Your Social Security Check
Here’s where it really hits home. If you’re collecting both Medicare and Social Security, your Part B premium is deducted directly from your monthly Social Security benefit. A higher premium means a smaller check, every single month.
So if you’re planning to delay Medicare enrollment, make absolutely sure you qualify for a special enrollment period first. A simple calendar mistake at 65 shouldn’t cost you money at 75, 85, or beyond.
