This page is general educational content about retirement income decisions. It is not investment, tax, or legal advice, and it is not a recommendation that any reader take or refrain from taking any action. Hypothetical examples are illustrative only and do not represent any specific household.
What the Window Is
"The gap years" is shorthand for the period between when a household stops earning a wage and when Required Minimum Distributions (RMDs) force taxable income out of tax-deferred accounts. For most households retiring in their early sixties, that window is eight to twelve years long; RMD age is 73 today and moves to 75 in 2033 under SECURE Act 2.0.
During the window, a household has something it never had before and will never have again: meaningful control over its own taxable income. There is no salary. There are not yet forced distributions. Whatever leaves the IRA, leaves by choice. Whatever stays, grows tax-deferred until 73.
The default behavior — "spend down taxable accounts first, leave the IRA alone until 73 forces the issue" — is intuitive and, for many households with substantial tax-deferred balances, materially suboptimal. The questions below are why.
Four Categories of Decision
Four categories of decision interact inside this window. Each is well-studied in isolation; the combined optimization is what makes the window distinctive.
For healthy married couples, the higher-earning spouse delaying to age 70 is frequently the better outcome on an actuarial basis; the lower-earning spouse often claims earlier. The break-even age relative to claiming at 67 typically lands near 81; if either spouse lives past that age, delaying the higher benefit wins. The survivor benefit makes the asymmetry larger.
Moving balances from traditional IRA to Roth IRA during otherwise low-bracket years accelerates tax payment in exchange for removing the asset from future RMDs entirely. The right amount is rarely all of it and rarely none; the optimization depends on current marginal bracket, expected RMD-era bracket, IRMAA implications, and survivorship.
The textbook ordering — taxable first, then tax-deferred, then Roth — is widely taught and, for households with substantial pre-tax balances, frequently dominated by other orderings that use the bracket-fill window. The choice cannot be evaluated in isolation from the conversion question.
Whether a household needs a guaranteed income floor on top of Social Security — and, if so, how large — is a sizing question, not a yes-or-no one. The candidate floor is the slice of essential expenses that, if a portfolio fell short, would force a real change in lifestyle. For some households the answer is "do nothing"; for some it is a SPIA or MYGA; in all cases the analysis is the same.
The Bracket-Fill Question
Consider a hypothetical married couple, both 62, retiring with $2M in a traditional IRA, $500K in a taxable account, and $100K in cash. No pension. Both intend to claim Social Security at 70. (All numbers illustrative.)
From 62 to 70, their only ordinary income is whatever they choose to take. Taking $0 from the IRA produces near-zero federal tax — and uses none of the 22% bracket those eight years offer. Taking enough from the IRA to fill the 22% bracket each year (roughly $100K of taxable income in 2026 numbers for MFJ) produces about $22K of federal tax per year and, across eight years, converts roughly $800K of pre-tax IRA into Roth for about $176K in tax.
Path A looks cheaper inside the gap years; no federal tax is paid. Across a lifetime — including a meaningful surviving-spouse window — Path B is typically the cheaper of the two for households with seven-figure traditional balances. The arithmetic that makes Path B work cannot be done outside this window; once RMDs begin, the household no longer controls the bracket.
The IRMAA Cliffs
IRMAA — the Income-Related Monthly Adjustment Amount — is the surcharge Medicare adds to Part B and Part D premiums when modified AGI crosses each of several thresholds. The structure is a cliff, not a curve: a single dollar of MAGI above a tier line moves the household to the next surcharge for the full year.
| MAGI (MFJ) | Part B / mo | Annual surcharge / couple |
|---|---|---|
| ≤ $212,000 | $185 | $0 |
| $212,001 – $266,000 | $259 | + $1,776 |
| $266,001 – $334,000 | $370 | + $4,440 |
| $334,001 – $400,000 | $480 | + $7,080 |
| $400,001 – $750,000 | $591 | + $9,744 |
| > $750,000 | $628 | + $10,632 |
The two-year IRMAA lookback adds a wrinkle: surcharges in a given year are determined by MAGI from two years prior. A household making a decision at age 64 affects its IRMAA bill at 66. This is the structural reason IRMAA accidents are common; the cost is invisible at the moment of the decision that produces it.
Large Roth conversions may deliberately cross IRMAA tiers — paying a one-year surcharge in exchange for escaping a structurally higher future bracket can be the right trade. Accidental tier crossings — a one-time capital gain, an unplanned RMD spike, a pension lump sum — usually are not.
Survivorship
Filing status changes from Married Filing Jointly to Single in the year following the death of one spouse. Income does not typically change much in the immediate aftermath; the brackets do — they are cut roughly in half, and IRMAA tiers for a single filer fall in parallel.
A couple with $180K of taxable income sits in the 22% bracket as MFJ. The same income, filed as Single, reaches into the 32% bracket. RMDs from a $2M IRA produce roughly $76K of taxable income; combined with a $50K pension and $50K of Social Security, a surviving spouse can cross from the 22% MFJ bracket into the 32% Single bracket, and across an IRMAA tier, without any change in financial behavior.
This is the strongest analytical case for aggressive Roth conversions during the MFJ years: every dollar moved to Roth is a dollar that does not push the eventual surviving spouse into a higher bracket. For couples with an age gap, the asymmetry compounds — the surviving-spouse window can be twenty years or longer, and the cumulative tax differential is often the largest single line in a lifetime cost projection.
Closing Note
Nothing on this page is a recommendation. The four categories above interact; the right course for any specific household depends on facts not described here, including state tax, age gap, health, charitable intent, the basis composition of taxable accounts, and a long list of other inputs.