If you have Medicare without any additional insurance, there will be some significant costs. If you have Medicare plus an Advantage plan, there will still be costs, probably significant ($1,000 or more I'm guessing). If you have Medicare plus a Part F plan, everything should be covered. We had no idea about the difference between Advantage and Part F plans (which are not generally advertised) until my husband was put on the list to receive a kidney just before he turned 65. He's younger, and we had group ins. for our two-person graphics company that cost $2,000/month–I hadn't been able to go on Medicare because that would have left him totally without ins. as the company group policy required a minimum of two people. The financial adviser at the transplant center told us that he needed to apply for Part F coverage (instead of an Advantage plan) as soon as he turned 65 and was eligible. At the time, he hadn't been on dialysis long enough (a year) to go on Medicare early: dialysis is $60,000/month, and our $2000 company plan only paid 80%, leaving $12,000/month for us to pay! The month he turned 65 he applied for a Part F plan through our regular broker, and we immediately owned absolutely nothing for dialysis. Two years later, he got a kidney, and the transplant cost not one penny!
That, in a nutshell, is the difference between Advantage plans and Part F (or even newer plans now available). Advantage plans tout that they cover vision and hearing, but they only pay a tiny amount toward glasses or aids. They pay part of the 20% that Medicare doesn't cover, but far from all, plus there are co-pays. Part F means that you pay nothing for anything medical: no co-pays, nothing. However, Part F does not pay for glasses or hearing aids, although they do cover all associated doc visits. Although I couldn't get Part F when my husband went on Medicare, I was able to elect Part F when we moved to another county by switching to an Advantage plan that didn't cover people in the county we moved to. I questioned whether it was worth it to pay so much more for Part F every month (at that time about $150 plus a $35 pharmacy plan (Part F doesn't cover pharmacy except "medical" pharmacy, like the horribly expensive anti-rejection drugs). Since I had experienced Stage 1 cancer (roughly a quarter million in expense, 20% of not covered by our company policy), I did elect Part F–and less than a year later learned that I'm now in the early stages of kidney failure, i.e., need to see a specialist every three months, with over a thousand in labs, all of it totally paid by Medicare and Part F.
Here's the short form: Anyone on Medicare has about $200 deducted from their SS before it arrives, their share of Medicare, exactly the same for everyone. Advantage plans cover some of most things, and some are totally free, while others cost modest amounts. However, you can be left with very large amounts to pay on your own. Again, the promised vision and hearing coverage is a token amount, far from the cost of glasses or aids. Part F coverage (you may need to find a broker to buy it and you can only elect to have it for either 60 or 90 days after you become eligible for Medicare) now costs close to $300 month for me (at 78), about $250 for my 73 YO spouse. You also need to have a separate pharmacy plan, which generally costs $35-40/month. When you see a doc or an audi, you pay nothing. I know that the surgery for a CI would cost nothing, but I haven't yet learned how much Part F pays toward the CI itself.
If you can predict that you'll have excellent health for the rest of your life when you become eligible for Medicare, it's fine to opt for an Advantage plan. However, if you later have cancer, need a transplant or some other horribly expensive surgery, you simply can't afford to opt for Advantage. My Part F plan monthly premium will increase next month when I turn 78, meaning that I'll pay the $200 deduction from SS, nearly $300 for Part F (up from just over $200), plus $35 for pharmacy coverage: Less than $550 to never pay for anything medical. I need to add that Advantage plans pay something toward dental while Part F pays nothing. Since I haven't had real teeth for years, that's not a problem for me, but it can be a significant cost for my spouse. We track the amounts we'd owe (the portion of our bills Medicare doesn't pay), and month after month it's more than we pay for Part F and pharmacy ins.