Most people spend decades focused on investment returns, then discover at retirement that the costly mistakes are structural — made before the first withdrawal — and difficult to reverse once the patterns are in motion.
A private transition-readiness assessment for major financial decisions.
The short answer: The recurring ones: retiring into a market drop with no cash runway, claiming Social Security by default rather than by sequence, ignoring the healthcare gap before Medicare at 65, and leaving pre-tax balances unmanaged until required withdrawals force the tax. Each is cheaper to prevent than to repair.
Direct Answer
The biggest retirement mistakes are not typically investment mistakes. They are structural planning mistakes — made before retirement — that determine how a portfolio is accessed, taxed, and drawn for 20-30 years. Claiming Social Security too early, failing to plan for Required Minimum Distributions, not establishing a withdrawal sequence, retiring without a healthcare bridge, and having advisors who don't coordinate are the most commonly cited structural errors. Each is avoidable with adequate lead time. Most are difficult or impossible to correct after the fact.
Common Mistakes
Claiming Social Security as a default step at retirement rather than modeling it — especially costly for the higher earner in a married couple, since that claiming age sets the eventual survivor benefit.
Drawing down accounts with no defined tax-sequencing logic, often depleting Roth assets early while pre-tax balances keep compounding toward larger future RMDs.
Ignoring the Required Minimum Distribution horizon until distributions actually begin, by which point the Roth-conversion window that could have reduced the tax bill has largely closed.
Retiring before 65 without a costed healthcare bridge plan, and separately underestimating how much Medicare itself costs once retired.
Letting estate documents and beneficiary designations go stale, so an outdated designation quietly overrides the current will.
Advisors working in isolation rather than coordinating, so the intersections — Roth conversions, estate structure, Medicare premiums — fall through the gaps.
Why This Decision Is Difficult
The retirement mistakes that matter most are invisible until they aren't. A suboptimal withdrawal sequence doesn't produce an immediate consequence — it produces a higher tax bill in year 15. A Social Security claiming decision made at 62 doesn't reveal its full cost until the surviving spouse's income is reduced 20 years later. An outdated beneficiary designation doesn't matter until an estate is being settled under stress. The nature of structural retirement mistakes is that they are low-feedback at the time they're made and high-consequence when they surface.
This creates a dangerous planning environment. The decisions with the longest time horizons and largest lifetime consequences are made in a period of transition and relative uncertainty — often without adequate time for deliberate analysis. Many retirees make the Social Security decision within months of leaving work, without modeling the survivor implications. Many choose a Medicare plan in the first enrollment window based on premium cost alone, without understanding the long-term switching constraints. The compressing timeline tends to force decisions that would benefit from more time.
The underlying problem is that most financial education and planning infrastructure is oriented around accumulation, not distribution. The skills and attention required to build a portfolio over 30 years are different from those required to draw one down intelligently — and the distribution phase often gets far less preparation time despite having equally consequential decisions.
Common Blind Spots
Claiming Social Security by default rather than by design. Many people claim Social Security when they retire, treating it as an automatic step rather than a decision to model. For married couples, the higher earner's claiming age determines survivor income — making it one of the most consequential decisions in the entire retirement plan.
No defined withdrawal sequence. Drawing from whichever account is convenient rather than following a tax-optimized sequence can cost significantly more in lifetime taxes. The optimal sequence — which varies by bracket, account mix, and income projections — should be explicit, not improvised.
Ignoring the RMD horizon. A large pre-tax IRA or 401(k) that was tax-deferred for decades will begin generating mandatory taxable distributions at 73. For people with significant pre-tax balances, these distributions may be larger than expected spending — and the tax cost can be reduced by Roth conversions made years earlier.
Retiring without a healthcare bridge plan. Employees often have healthcare subsidized by employers for decades and have little awareness of true costs. COBRA, ACA marketplace premiums, and out-of-pocket costs can total an estimated $20,000–$40,000 per year for a couple in their early 60s — an amount that varies by plan, region, and any marketplace subsidy, and often comes as a shock.
Outdated estate documents. Wills and beneficiary designations created in the accumulation years may not reflect current family structure or assets. An ex-spouse named as IRA beneficiary inherits it regardless of what the current will says. Estate documents not reviewed in 5+ years are typically stale in at least one material way.
Treating Medicare as free or near-free. Part B premiums, Part D costs, Medigap or Advantage premiums, and services Medicare doesn't cover (dental, vision, hearing, long-term care) add up to real money. IRMAA surcharges for higher-income retirees can add thousands more annually. Many retirees budget less than half of their actual healthcare costs.
No advisor coordination. A financial advisor who doesn't communicate with the CPA doesn't know that a Roth conversion will trigger IRMAA. An estate attorney who doesn't know the retirement account balances creates a beneficiary structure misaligned with the tax plan. Coordination among advisors is where retirement planning either holds together or develops expensive gaps.
Underestimating the length of retirement. A couple retiring at 62 has a meaningful probability that at least one spouse lives past 90. A plan designed for 20 years may be tested for 30. Longevity risk — the risk of outliving the plan — is the organizing concern of retirement income planning, and it is systematically underweighted by retirees who anchor to average life expectancy rather than planning for the upper tail.
Questions Worth Asking
Have you modeled all three Social Security claiming scenarios — your age, your spouse's age, and the survivor benefit at each combination? For a married couple, this is a multi-variable optimization, not a simple break-even calculation. A financial planner or Social Security optimization tool should run the full scenario matrix.
What is your written withdrawal sequence for the first 10 years of retirement? This should specify which account type is drawn first, in what amounts, and under what conditions the sequence would be modified. If the answer is "whatever we need," that is not a plan.
What are the projected RMDs from your pre-tax accounts at age 73, 75, and 80? The IRS provides RMD tables based on account balances and age. Your CPA or financial planner should be able to model these projections and evaluate whether Roth conversions before 73 would reduce the lifetime tax cost.
What is your specific healthcare plan from retirement to age 65? Name the coverage source, estimate the monthly cost, and confirm it has been verified as available. A plan that says "figure out healthcare when the time comes" is a meaningful unaddressed risk.
When were your beneficiary designations last reviewed? List every retirement account, life insurance policy, and transfer-on-death account and confirm the current beneficiary on each is accurate and intentional. This should be done annually.
Have you stress-tested the retirement plan against living to age 90 or 95? Longevity planning requires modeling spending, healthcare costs, and portfolio performance across a longer horizon than most people assume. The plan should remain solvent in the optimistic scenario, not just the average one.
Do your financial advisor, CPA, and estate attorney communicate directly with each other? If the answer is no, identify the specific intersections — Roth conversion and tax planning, beneficiary designations and estate structure, income levels and Medicare premiums — and ensure someone is responsible for coordinating across them.
What does the surviving spouse's financial picture look like? Map out the income, accounts, and expenses the surviving spouse would face. Does the plan work for them independently, or does it depend on both spouses' continuing presence?
What Most People Miss
The most important thing most people miss is that retirement mistakes are front-loaded. The decisions that most affect outcomes over a 25-year retirement are made in the 1-3 years before and immediately after retiring. Social Security timing, account withdrawal sequencing, Medicare plan selection, Roth conversion windows, and estate document review all have their most consequential windows in this period. Waiting until retirement begins to address these areas means several of the best planning windows have already closed.
The second thing most people miss is the distinction between a mistake of omission and a mistake of commission. A wrong investment is a mistake of commission — you did something that didn't work. Most structural retirement mistakes are mistakes of omission — decisions that were never explicitly made, defaults that were never examined, coordinations that were never arranged. The advisor who was never asked to run the RMD projections. The Social Security decision made by default rather than analysis. These omissions are harder to see precisely because nothing was done.
Finally, most people underestimate the degree to which these decisions interact. The Social Security claiming age affects how much needs to be drawn from the portfolio in early retirement, which affects the withdrawal sequence, which affects bracket management, which affects the Roth conversion strategy, which affects future RMDs, which affects Medicare premiums. Optimizing each decision in isolation — without modeling the interactions — produces a plan that looks good on paper and underperforms in practice. The planning work that surfaces these interactions is the planning work most worth doing.
The costliest retirement mistakes are rarely investment mistakes — they are structural planning failures made before the first withdrawal, often mistakes of omission rather than commission: a decision never explicitly made, a default never examined. These errors are low-feedback at the time they're made and high-consequence once they surface, which is exactly what makes them easy to miss. Because Social Security timing, withdrawal sequencing, Medicare selection, and estate documents all interact, optimizing any one in isolation can still leave the overall plan exposed. Addressing them in the years before and immediately after retirement, while the decision windows are still open, is what keeps them from compounding.
Axel Index
Most people discover planning gaps after decisions are already in motion.
The Axel Index was built to help identify potential blind spots before they become difficult to reverse.
What is the biggest mistake people make when retiring?
The most commonly cited structural mistake is claiming Social Security too early — particularly the higher-earning spouse in a married couple — which permanently reduces a benefit that may need to support a surviving spouse for decades. The second most consequential mistake is not having a defined withdrawal sequence, which leads to drawing accounts in an order that creates unnecessary tax costs over a multi-decade retirement. Both are decisions of default rather than design — made without explicit modeling of the long-term consequences.
Why is Social Security timing such a costly mistake to get wrong?
Social Security timing is particularly consequential because the claiming decision is largely permanent after 12 months, claiming at 70 rather than 62 can produce a monthly benefit roughly 75% higher — the combined effect of the early-claiming reduction and the delayed retirement credits of 8% per year earned to age 70 — and for married couples the survivor benefit is locked in at whatever the deceased spouse was receiving. A higher earner who claims at 62 instead of 70 may reduce a surviving spouse's income for 20 or more years. The lifetime income difference between the best and worst claiming strategies for a married couple can exceed $200,000 in present value terms.
What is a withdrawal sequence mistake?
A withdrawal sequence mistake occurs when retirement accounts are drawn in an order that creates unnecessarily high lifetime tax costs. A common error is depleting Roth accounts early (consuming tax-free assets) while leaving pre-tax accounts to compound and generate larger future RMDs. Another is drawing taxable brokerage accounts last, missing the opportunity to harvest gains at lower capital gains rates in early retirement when income may be lower. The optimal sequence depends on current and projected income, bracket positioning, IRMAA thresholds, and the estate planning goals for each account type.
What happens if I don't plan for Required Minimum Distributions?
Failing to plan for RMDs typically results in a significant and often unexpected tax burden beginning at age 73, when mandatory withdrawals from pre-tax accounts can push income into higher brackets, trigger Medicare IRMAA surcharges, and increase the taxable portion of Social Security benefits. For people with large pre-tax balances accumulated over decades, RMDs can generate more taxable income than actual spending needs — a problem that Roth conversions in the years before 73 might have mitigated. By the time RMDs begin, the primary optimization window has largely closed.
What is the most common healthcare mistake retirees make?
The most common healthcare mistake is retiring before 65 without a funded, specific plan for covering healthcare costs until Medicare eligibility. Many people assume COBRA will be inexpensive — it typically isn't, often costing an estimated $1,500–$3,000 per month for a couple, and varying by plan, age, and region — or that ACA marketplace coverage will be easy to navigate without premium shock (HealthCare.gov shows current marketplace prices and any subsidies). Others retire expecting retiree health benefits from a former employer, only to find those benefits have been reduced. Not having a costed healthcare bridge plan is one of the most common reasons early retirements become financially stressed in the first years.
What mistake do people make with estate planning at retirement?
The most common estate planning mistake at retirement is assuming that documents created years earlier are still current and adequate. Wills, powers of attorney, and healthcare directives written during the accumulation years may not reflect current family circumstances, account structures, or estate planning law. More consequentially, beneficiary designations on retirement accounts — which legally override the will — are frequently outdated. An ex-spouse, a deceased parent, or a suboptimal trust structure as beneficiary can create significant unintended consequences that a will cannot correct after the fact.
Is retiring too early a mistake?
Retiring early is not inherently a mistake, but it creates compounding structural challenges that require specific advance planning: a longer portfolio withdrawal period increases sequence-of-returns risk; a healthcare coverage gap exists before Medicare at 65; and claiming Social Security early to meet income needs permanently reduces benefits for the claimant and potentially the surviving spouse. Each challenge is manageable individually with adequate planning. The mistake is not early retirement itself — it is retiring early without specifically addressing these three compounding effects as part of the transition plan.
What do most people not know about Medicare costs?
Most pre-retirees significantly underestimate total Medicare costs. Between Part B premiums (the base premium is set annually — confirm the current amount at SSA.gov), Part D drug coverage, Medigap or Advantage plan premiums, dental, vision, hearing costs (which Medicare does not cover), and potential IRMAA surcharges for higher-income retirees, a couple may spend an estimated $10,000–$20,000 or more per year on healthcare even with Medicare coverage — actual costs vary by plan, region, and income. The assumption that Medicare means low healthcare costs is one of the most widespread and consequential misconceptions in retirement planning.
What is the advisor coordination mistake in retirement?
The advisor coordination mistake is having a financial advisor, CPA, and estate attorney who each work in isolation — optimizing their respective area without visibility into what the others are doing. The highest-value retirement planning opportunities tend to occur at the intersections: Roth conversions require both tax modeling and investment reallocation; estate plans must account for beneficiary tax treatment under post-SECURE Act rules; Social Security decisions affect income, Medicare premiums, and portfolio withdrawal rates simultaneously. Without deliberate coordination, these intersections produce planning gaps rather than integrated outcomes.
What is the Axel Index?
The Axel Index is a private educational assessment designed to help people approaching major financial transitions identify structural planning gaps before decisions are made and become difficult to reverse. It covers income sequencing, tax strategy, healthcare coverage, Social Security timing, estate documents, and advisor coordination. It is an educational tool and does not constitute financial, investment, tax, or legal advice. It is designed to complement — not replace — the guidance of qualified professionals.
Primary sources
Tax, benefit, and premium figures are set by statute and adjusted over time. Where a figure changes, this page explains how the rule works and points to the primary source for the current amount rather than stating a number that could become out of date. Confirm current figures against these sources or a qualified professional.
Required minimum distributions — current rules and tables — IRS