Turning 65? Here's the order to do things in.

If you are coming up on 65, you have probably noticed the mail. Envelopes that look official but are not. Envelopes that are official and still make no sense. Phone calls from people who somehow know your birthday.

Here is the honest version, in the order it actually matters.

1. Find out whether you need to do anything yet

The first question is not “which plan?” It is “am I still covered by an employer?”

If you are still working and covered by an employer plan — yours or a spouse’s — the right move depends on how that coverage works and how large the employer is. Some people should enroll at 65 anyway. Some people should wait, and enrolling early would cost them money for no benefit.

This is the single most common place people go wrong, in both directions. It is worth one phone call before you do anything else.

2. Know when your window opens

There is a window around your 65th birthday when you first sign up. It opens a few months before your birthday month and stays open for a few months after it.

When inside that window you enroll can change when your coverage starts. And missing the window altogether can mean a late enrollment penalty that stays attached to your premium — not a one-off fee, an ongoing one.

So: put your own dates on a calendar. Not roughly. The actual dates.

3. Write two lists before you look at a single plan

This is the part people skip, and it is the part that decides whether you are happy in eighteen months.

List one: your doctors. Everyone you want to keep seeing, by name, including specialists.

List two: your prescriptions. Exact names, exact doses. Not “something for blood pressure.”

Plans differ enormously on both. Two plans with almost identical premiums can treat your particular doctors and your particular medications completely differently. Without those lists, any comparison is guesswork dressed up as advice.

4. Understand the one real choice

Strip away the marketing and nearly everyone is choosing between two paths:

• Original Medicare, usually with a Supplement and a separate Part D drug plan. No network to worry about, more predictable costs, generally a higher monthly premium.
• A Medicare Advantage plan, which bundles it together, usually including drug coverage, often with extra benefits — and with a network, plan rules, and a yearly cap on what you pay out of pocket.

Neither is correct for everybody. The right one depends on your two lists, how much you travel, and whether you would rather pay a steadier amount every month or a smaller one with more variation when you use care.

There is one timing detail worth knowing here: when you first become eligible, there is generally a period where a Supplement can be bought without health questions. Outside that period, medical underwriting may apply. That makes the first decision a little weightier than the ones after it.

5. Then, and only then, compare plans

With your dates known, your doctors listed and your prescriptions written down, comparing plans takes about half an hour and the answer is usually obvious.

Without those things, it takes weeks and you still will not be sure.

The two mistakes I see most

Choosing on premium alone. The monthly number is the easiest to compare and the least useful on its own. What matters is what you will actually pay across a whole year, given the care you actually use.

Waiting because it is overwhelming. The deadlines are real. If the whole thing has got on top of you, that is a completely normal reaction to a genuinely confusing system — but do not let it run the clock down.

If you would like someone to go through this with you, that is what I do. Bring your two lists and your questions. There is no charge for the conversation and no obligation at the end of it.