Bill retired at 61 with $1.2 million and a tax bill of almost nothing.
For ten years he lived off a savings account, reported barely any income, and told everyone at church he had beaten the IRS.
Then he turned 73. The required withdrawals started. His wife died the following spring, which moved him into single tax brackets that are half as wide. And his Medicare premium went up, because of a tax return he had filed two years earlier and forgotten about.
Bill did not beat the IRS. He scheduled an appointment with it, twelve years out, and then forgot he had made it.
Here is the thing that would have fixed it, and it fits in one sentence.
You pay tax on money now, so you never pay tax on it again.
That is a Roth conversion. Everything else in this article is just working out whether that trade is good for you, and the answer comes down to one comparison: is the rate you pay today lower than the rate you would have paid later?
If yes, convert. If no, do not. If you have no idea, you are in the same position as almost everyone, and that is what the next 3,000 words are for.
A conversion is not an investment decision. Nothing about your portfolio changes. You are simply choosing which decade to pay the tax bill in.