Open enrollment for health insurance starts Thursday. So millions of people 65 and older are getting lots of ads in the mail for insurance that covers what Medicare doesn’t.

I got my first taste this year, as I approached 65. I was Medicare to-be. In just a few months, I received 40 mailings from insurers and brokers — plus Medicare’s own 152-page guide to Medicare.

Now, because of open enrollment, the mail’s coming again.

Here’s what I learned my first time around:

1) Medicare is not free.

2) Choosing among insurance plans that cover what Medicare doesn’t is complicated, and wrong decisions can cost a lot of money.

3) I am no dope, but I expect to be confused by this every October until I die.

The graphic below shows where my direct-mail solicitations came from — I have thrown away SO much mail from AARP since I turned 50.

I’ve learned one other thing. I still work, so my wife and I have insurance through my company. But when I retire… we’ll pay a consultant to guide us through Medicare. We don’t trust ourselves to get it right. And we’re no dopes.

(Janet Nguyen/Marketplace)