How Long Will Your Retirement Actually Last? The Question Most People Get Wrong -

Published by Turn Back Clock | Category: Longevity & Retirement

Most people spend more time planning a two-week holiday than they spend planning for a retirement that could last three decades. That is not a criticism — it is a structural problem. Retirement feels abstract and distant until it arrives. And by the time it arrives, the decisions that determine how long your money lasts have already been made.

The single most consequential variable in all of retirement planning is also the one most consistently underestimated: how long you will actually live.

The Numbers Most Retirement Plans Are Built On Are Wrong

Most retirement plans are still built around average life expectancy figures at birth. The problem is that those figures are the wrong numbers entirely. If you make it to retirement age, you have already survived the accidents, diseases, and early-life risks that pull down the average. Your relevant life expectancy is not the one calculated at birth — it is the one calculated from where you are now.

Here is what the current data actually shows:

A 65-year-old man in the US today can expect to live to approximately 84
A 65-year-old woman can expect to live to approximately 86
That translates into a potential distribution horizon of at least 20 to 30 years — not the 15 to 20 years many older retirement models assumed

And those are averages. If you are in good health, have a family history of longevity, are not a smoker, and exercise regularly, your personal life expectancy may be meaningfully higher than the statistical average for your age group.

The practical implication: most retirement plans are built for 20 years. Actuarial data says you may need 30. That 10-year gap is not a rounding error. It is a structural problem that can turn a comfortable retirement into a financially precarious one.

Why Most People Underestimate How Long They Will Live

Research from the TIAA Institute identifies a significant gap in what it calls longevity literacy — the ability to accurately estimate how long you are likely to live. The data shows that people consistently and substantially underestimate their own life expectancy, often by 5 to 10 years.

There are several reasons for this:

People anchor on the ages at which their parents or grandparents died, without accounting for the significant improvements in medicine and lifestyle that have extended longevity since then
Healthcare advances mean that conditions that killed previous generations are now manageable chronic diseases that people live with for decades
US life expectancy at birth rose to 79 in 2024 — an increase of more than six months compared to 2023 alone — and the trend continues upward
People in good health at 65 have meaningfully better survival odds than the average figure suggests

The consequence of underestimating longevity is that people plan for a shorter retirement than they will actually have, save less than they need, and withdraw at rates that deplete their savings before their life does.

The Real Risk: Outliving Your Money

Longevity risk — the risk of outliving your retirement savings — is the defining financial challenge of modern retirement. It is also the one that makes every other retirement risk worse.

Consider what happens when retirement extends from 20 years to 30:

A portfolio that suffers a significant market decline in years 3 to 5 of a 20-year retirement may recover. Over 30 years, the same early-sequence loss can permanently impair the portfolio ability to sustain withdrawals
Inflation compounds relentlessly: at 3% annual inflation, ,000 per month in 2026 has the purchasing power of approximately ,600 per month by 2046
Healthcare costs escalate with age: a healthy 65-year-old couple retiring in 2026 needs to have saved approximately 18,000 just to cover healthcare expenses, according to the 2026 Milliman Retiree Health Cost Index

None of these problems are fatal to a well-planned retirement. But each of them becomes dramatically harder to manage if you are planning for 20 years and living for 30.

How to Find Out Where You Actually Stand

The first step in planning for the right retirement length is getting a realistic estimate of your own personal longevity — not the population average, but an estimate based on your actual lifestyle, health habits, and risk factors.

This is exactly what our free longevity quiz at Turn Back Clock is designed to give you. In two minutes, it asks you the eight lifestyle questions with the strongest evidence for predicting longevity — exercise, diet, sleep, smoking, stress, alcohol, and more — and generates a personalised estimate based on your specific profile, not the average.

→ Take the free Turn Back Clock longevity quiz at TurnBackClock.com

Knowing your personal longevity estimate is not about anxiety. It is about planning with the right number. If your estimate suggests you are likely to live into your late 80s or beyond, that changes how much you need to save, when you should start drawing down, and how aggressively you should manage your health now to protect that retirement.

What to Do With the Number

Once you have a realistic longevity estimate, here is how to apply it to your retirement planning:

1. Recalculate Your Withdrawal Rate

The standard 4% withdrawal rule was designed for a 30-year retirement. If your longevity estimate suggests 35 years or more, a 3% to 3.5% rate may be more appropriate. The difference between 3% and 4% on a million portfolio is 0,000 per year — meaningful, but manageable if planned for in advance.

2. Build a Realistic Healthcare Budget

The 2026 Milliman data is unambiguous: a healthy 65-year-old couple can expect to spend an average of 37,000 on healthcare expenses over their remaining lifetime under Original Medicare with Medigap coverage. Factor it into your planning as a hard number, not a vague estimate.

3. Think About Healthspan, Not Just Lifespan

A retirement that lasts 30 years is only an asset if those years are spent in good health. The fastest-growing body of longevity research focuses not on how long people live, but on how many of those years are spent in good physical and cognitive health — what researchers call healthspan. The habits that extend healthspan are the same ones that extend lifespan: exercise, diet, sleep, stress management, and targeted supplementation.

This is exactly what the Turn Back Clock quiz and our longevity content is designed to help you with — not just knowing your number, but actively improving it.

The Most Important Retirement Decision You Can Make Right Now

It is not choosing the right fund allocation. It is not picking the right withdrawal strategy. It is deciding, today, to take your physical health as seriously as your financial health.

Every year of additional healthy life you can add through lifestyle changes is a year your savings do not have to stretch as thin. Every medical crisis you avoid through preventive health investment is a potentially six-figure saving on your healthcare budget.

Start by knowing your number.

→ Take the free Turn Back Clock longevity quiz at TurnBackClock.com

Key Takeaways

A 65-year-old retiring today should plan for 20 to 30 years of retirement — not the 15 to 20 years many older models assumed
Most people significantly underestimate their own life expectancy, often by 5 to 10 years, according to TIAA Institute research
Longevity risk — outliving your money — makes every other retirement risk worse
A healthy 65-year-old couple needs approximately 18,000 in savings for healthcare alone in retirement, according to the 2026 Milliman data
Knowing your personal longevity estimate is the first step in planning with the right numbers
Healthspan — the number of healthy, functional years — matters as much as lifespan for retirement quality

References

1. PLANADVISER / HousingWire. Retirement planning faces longevity risk as Americans live longer. February 2026. https://www.housingwire.com/articles/living-longer-retirement-risk/

2. Kiplinger. How to Manage Longevity Risk in Retirement. June 2026. https://www.kiplinger.com/retirement/retirement-planning/how-to-manage-longevity-risk-in-retirement

3. The Top Minds. Longevity Risk: You May Live 30 Years in Retirement. March 2026. https://thetopminds.com/pages/article-longevity-risk

4. Milliman. 2026 Retiree Health Cost Index. June 2026. https://www.milliman.com/en/insight/retiree-health-cost-index-2026

5. Experian. What Is Longevity Risk for Retirees? 2026. https://www.experian.com/blogs/ask-experian/what-is-longevity-risk-for-retirees/