The fundamental principle is simple: pay taxes when the rate is lowest.

As Michael Kitces puts it: "The basic principle for maximizing long-term wealth is relatively straightforward: you should pay your taxes when the rate will be lowest."

A Roth conversion makes sense when your tax rate today is lower than what you — or your heirs — would pay on that money in the future. Everything else flows from that core idea.

Reference: Kitces, "When a Roth Conversion is Bad Even if Tax Burdens Go Up"

Tax arbitrage means creating wealth by shifting income from higher-tax years to lower-tax years.

Kitces defines it clearly: "The value of income harvesting strategies is 'tax-rate arbitrage' — the opportunity to shift income from higher-tax-rate years (in the future) to lower tax rate years (today) — creating wealth through the difference in prospective tax rates."

In practice, this means: if you can convert pre-tax dollars at a 22% rate today and avoid a 32% rate in the future, you've captured 10 percentage points of tax savings on every dollar converted. That difference is the arbitrage.

Reference: Kitces, "Navigating Income Harvesting Strategies"

Not necessarily. Conventional wisdom says defer, defer, defer — but that approach can backfire. Kitces explains: "It turns out that sometimes the best way to save on taxes is to pay them as soon as possible, even if it means creating income before the end of the year in order to do so."

Deferring too much into a traditional IRA can cause your account to grow so large that future Required Minimum Distributions (RMDs) push you into a higher bracket than you're in today. Converting strategically in lower-income years — such as early retirement, before Social Security begins, or before RMDs kick in — can reduce your lifetime tax bill significantly.

Reference: Kitces, "End-of-Year Roth Conversions and Capital Gains Harvesting"

Not exactly — and this is an important distinction. Estate value measures the size of the pile, not how much of it you or your heirs actually keep after taxes. A traditional IRA is a tax-deferred asset. When you withdraw from it in retirement, you pay income tax at your marginal rate. When your heirs inherit it, they owe income tax on every dollar they withdraw — potentially during their peak earning years.

The better goal is to minimize total taxes paid across your lifetime and your heirs'. A

smaller Roth estate can be worth more than a larger traditional IRA estate, once taxes are accounted for.

The right question isn't: "Which scenario produces the biggest estate?" The right question is: "What tax rate do I pay today vs. what rate would I (or my heirs) pay later?"

More than most people realize. Kitces makes this point explicitly: "The proper comparison of tax rates to evaluate potential tax rate arbitrage is not the current versus future rate of the account owner, but the account owner's future tax rate compared to the heir's tax rate in the future."

If you are in a lower tax bracket in retirement than your heirs will be during their working years, converting now — even if it doesn't benefit you personally — can be a powerful wealth transfer strategy. Under current law, most non-spouse beneficiaries must fully distribute an inherited IRA within 10 years. If your heirs are high earners, every dollar from an inherited traditional IRA gets stacked on top of their existing income and taxed

accordingly.

A Roth, by contrast, passes to heirs income-tax-free.

Reference: Kitces, "Navigating Income Harvesting Strategies"

The break-even point is how many years it takes for the future tax-free benefits of a Roth to outweigh the upfront tax cost of converting. It's a useful concept, but it's a secondary lens — not the primary question.

The more fundamental question is always the tax rate differential: If you pay taxes today at a lower rate than you (or your heirs) would pay later, the conversion is mathematically favorable — regardless of how many years it takes to "break even."

If you pay taxes at a higher rate today, the conversion likely doesn't make sense — no no matter how long you wait.

Break-even analysis is most useful for stress-testing timing assumptions. But it should follow from the tax rate comparison, not replace it.

Yes — significantly. Paying the tax bill from funds outside the IRA (such as a savings or taxable brokerage account) is generally more effective because it allows the full converted amount to grow tax-free inside the Roth. Paying taxes from the converted funds themselves reduces the amount actually working for you in the Roth and extends the break-even timeline.

Wade Pfau's research supports this: his simulations consistently show that Roth

conversions funded by outside assets outperform those where taxes are paid from the account itself, all else equal.

Reference: Pfau, "How a Roth Conversion Could Save You Money in the Long-Term"

Yes. Converting too aggressively in a single year can push you into a higher bracket than you would have faced in the future — defeating the purpose entirely.

Kitces illustrates this with a case study where a couple converting their entire IRA at once drives their marginal rate from 15% all the way to 39.6% — far higher than the 28% future rate they were trying to avoid.

The solution: partial, systematic conversions that "fill up" lower tax brackets each year without crossing into higher ones. This is often called "bracket filling" and is one of the most powerful and practical conversion strategies available.

Reference: Kitces, "Using Systematic Partial Roth IRA Conversions"

Your stated tax bracket is not always your true cost of converting. Wade Pfau introduces the concept of the effective marginal tax rate (EMR) — the actual rate on each additional dollar of income, once you account for "tax non-linearities" such as:

The Social Security tax torpedo — additional income can cause more of your Social

Security benefit to become taxable, sharply increasing your true rate IRMAA surcharges — higher income can trigger Medicare premium surcharges ACA premium cliff — for pre-Medicare retirees, income above certain thresholds can eliminate subsidies

These hidden effects can make your actual marginal rate significantly higher than your nominal bracket — sometimes by 10–20 percentage points. Pfau's "tax map" methodology visualizes these non-linearities year by year, allowing for smarter conversion timing.

Reference: Pfau & Elsasser, "Managing Taxes in Retirement Using the Effective Marginal Tax Rate"

The ideal windows are years when your taxable income is temporarily lower than it will be in the future. Common opportunities include: Early retirement, before Social Security begins — often the lowest-income years of a retiree's life

As Pfau notes, the strategy is about finding and filling those lower-rate windows

systematically — not converting all at once.

Reference: Pfau, "Retire with Style, Episode 155: Navigating Roth Conversions"

Boldin lets you model different conversion scenarios and see the projected impact on your retirement income, tax burden, and estate outcomes over time. You can adjust conversion amounts, timing, and compare traditional vs. Roth withdrawal strategies side by side. Because the math gets nuanced — especially when IRMAA, Social Security taxation, and heirs' tax rates are involved — we always recommend working through your specific numbers in the Boldin planner and consulting a tax advisor or fee-only financial planner for personalized guidance.

Boldin is not a financial advisor. This content is for educational purposes only. Please

consult a qualified tax professional for advice specific to your situation.