Roth conversions: the income question hiding inside a growth decision.
Roth conversions are usually sold as a growth story. They are actually an income story — and getting that framing wrong is why most Roth dollars end up in the wrong hands, at the wrong time, for the wrong reason.
For households with meaningful pre-tax retirement balances, the years between when the paycheck stops and when required minimum distributions begin are a kind of tax-planning twilight. Wages have ended. Social Security may not have started. Brackets are temporarily low. RMDs have not yet forced income back up. It is, for many families, the single most valuable tax window of their lives — and most of it goes unused.
This is where Roth conversions earn their reputation. Done deliberately, a conversion moves dollars from a future, almost-certainly-higher tax bracket into today's almost-certainly-lower one. You pay the tax once, on your terms, in the year you choose, and every dollar of growth and every dollar of future withdrawal comes out tax-free.
The real benefits are worth stating plainly. A well-modeled conversion program can fill the 12% and 22% brackets during the gap years instead of watching those same dollars come out later at 24%, 32%, or higher once RMDs and Social Security stack on top of each other. It can soften the surviving-spouse tax cliff, when the household drops from married-filing-jointly brackets into single brackets often on nearly the same income. It can shrink the pre-tax balance that heirs will otherwise be forced to drain within ten years under the SECURE Act's inherited-IRA rule — frequently during their own peak earning years. And it creates a bucket of income that does not count against IRMAA, does not push capital gains into the next bracket, and does not shrink with the next tax-law change.
The negatives are just as real, and they are the reason a conversion should never be a reflex. The tax has to be paid, ideally from non-retirement dollars, or the math quietly falls apart. A conversion done in the wrong year can trigger IRMAA surcharges on Medicare Parts B and D two years later. It can wipe out ACA premium subsidies for households bridging to 65. It can push long-term capital gains from the 0% bracket into the 15% bracket. It carries state income tax in most states. And since recharacterization was eliminated in 2018, a conversion is a one-way door — the check you write in April cannot be unwritten.
This is where the choice of professional matters more than most families realize. A growth-focused advisor looks at a Roth conversion and sees a portfolio question: which account will compound to the largest ending balance? That framing almost always argues for converting aggressively, because tax-free compounding wins on a spreadsheet with a long enough time horizon. But retirement is not a spreadsheet with a long time horizon. It is a sequence of income needs, tax brackets, Medicare thresholds, and a surviving spouse who will eventually file as single.
An income-focused professional starts from a different question entirely: what does spendable, after-tax income look like across both of your lifetimes, and what conversion schedule produces the most of it with the least fragility? That framing often argues for smaller, steadier conversions across many years — filling specific brackets on purpose, coordinating with Social Security timing, respecting IRMAA tiers, and stopping when the marginal cost of the next converted dollar exceeds the marginal benefit to future income. The answer is rarely 'convert everything.' It is almost never 'convert nothing.' It is usually 'convert this much, this year, for this reason.'
The most quietly damaging mistake in this whole conversation is one we see constantly: households pay the conversion tax, move the money into a Roth, and then never spend it. The Roth becomes the 'best' account — the one you don't touch, the one you save for last, the one that feels almost sacred. And so it sits, untouched, while the pre-tax IRA gets drawn down and the taxable brokerage gets drawn down, until one spouse passes, the survivor moves into single brackets, and eventually the Roth passes to the children — who must empty it within ten years, often during their highest-earning decade.
That is not a legacy plan. That is a planning failure wearing a legacy plan's clothing. The tax was paid by the parents. The tax-free growth was harvested by the parents. And then the tax-free income — the entire point of the exercise — was handed to heirs instead of being used by the people who paid for it.
In an income-first plan, the Roth has a job, and that job is usually spendable, tax-free income late in retirement — precisely when the surviving spouse is most vulnerable to the widow(er)'s tax penalty, when RMDs on remaining pre-tax dollars are largest, and when a tax-free withdrawal is worth the most. Leaving the Roth to heirs is a fine outcome; leaving the Roth to heirs by default, because no one ever built a plan to draw from it, is not.
The right answer to 'should I do a Roth conversion?' is almost never yes or no. It is a multi-year conversion schedule, sized to your bracket, coordinated with your income sources, stress-tested against the surviving-spouse picture, and paired with a plan to actually use the Roth dollars during your own lifetime. That is income planning. Anything less is a growth bet dressed up as tax strategy.