Living to 100 is not the average retirement outcome, but it is a useful stress-test for a financial plan. Someone retiring at 65 and living to 100 would need to support 35 years of retirement, while someone leaving work at 55 could face a retirement lasting 45 years.
That changes the planning question. Instead of asking only whether your savings can support the first decade after work, you need to consider how income, investments, healthcare, inflation, taxes, and spending could evolve over three or four decades.
Current Social Security projections illustrate why longevity deserves attention. For 2026, period life expectancy at age 65 is approximately another 18.4 years for men and 20.9 years for women, placing the averages in the mid-80s. An average, however, is not an expiration date. Some people will live considerably longer, which is why testing a plan through ages 90, 95, and 100 can be valuable.
The goal is not to assume you will definitely reach 100. It is to avoid building a retirement that works only if you do not.
Why Does Longevity Change Retirement Planning?
A longer life means more years of housing, food, utilities, insurance, taxes, and other everyday expenses. It also creates more time for inflation to increase those costs and more opportunities for major healthcare, home, or family expenses to arise.
Longevity also affects portfolio risk. A retiree with a 35-year horizon may need investment growth well into retirement rather than moving everything into cash or short-term investments at age 65.
At the same time, spending does not necessarily remain constant for 35 years. Travel and entertainment may be higher during the active early-retirement years, while healthcare and support needs can become more important later.
That is why planning to age 100 should be based on a flexible income strategy rather than simply multiplying today’s annual expenses by 35.
Step 1: Model More Than One Life Expectancy
A retirement projection based on one assumed age can give a false sense of certainty. Instead, compare several horizons and see how each one changes the outcome.
Useful scenarios might include:
- Age 85: A shorter retirement scenario that still extends well beyond the first decade after leaving work.
- Age 90 or 95: Longer scenarios that test whether spending and withdrawals remain sustainable as retirement progresses.
- Age 100: A longevity stress test designed to reveal whether the plan has enough flexibility for an unusually long life.
If a plan works comfortably to 85 but runs out of liquid assets at 92, that is useful information. You can then evaluate whether additional savings, lower withdrawals, later retirement, different Social Security timing, or other resources improve the outcome.
If you are still determining how many years your existing assets can reasonably support, reviewing when you can retire can help connect the retirement date with the length of time those resources may need to last.
Step 2: Build a Spending Plan That Changes Over Time
A 35-year retirement should not be modeled as though every year will look identical.
Start with today’s expected retirement lifestyle and divide spending into areas that may behave differently over time. Housing and basic living costs may remain relatively stable before inflation, while travel may decrease later in life and healthcare costs may increase.
A practical long-range spending model should account for:
- Essential Living Costs: Housing, food, utilities, insurance, transportation, property taxes, and other recurring expenses.
- Lifestyle Spending: Travel, hobbies, entertainment, gifts, and other spending that may be higher during the active retirement years.
- Healthcare and Care Needs: Medicare premiums, out-of-pocket healthcare costs, prescription expenses, and the possibility of long-term support or care.
- Large Irregular Expenses: Vehicles, home repairs, relocation, family assistance, and other costs that do not fit neatly into a monthly budget.
The distinction between essential and flexible spending becomes particularly useful during a long retirement. If markets perform poorly for several years, reducing discretionary expenses temporarily can be less disruptive than cutting necessities.
Step 3: Give Lifetime Income an Important Role
Income that continues for life becomes increasingly valuable when retirement lasts longer than expected.
Social Security and applicable pensions are important because they do not depend on how long an investment portfolio lasts. Certain annuity structures can also provide lifetime payments, although costs, liquidity, inflation protection, insurer strength, and contract terms need to be evaluated carefully.
The objective is not necessarily to guarantee every dollar of future spending. Instead, consider how much of your essential lifestyle could be supported by income that does not disappear if you live to 95 or 100.
A household whose pension and Social Security cover most basic expenses can generally approach investment withdrawals differently from a retiree whose portfolio funds nearly everything.
Step 4: Use Social Security as Part of Longevity Planning
Social Security deserves particular attention when planning for a potentially long retirement because retirement benefits continue for life and generally receive annual cost-of-living adjustments.
For people born in 1960 or later, full retirement age is 67. Starting at 62 can reduce the monthly benefit by as much as 30% compared with waiting until full retirement age.
Delaying beyond full retirement age can increase the benefit further. For people born in 1943 or later, delayed retirement credits generally increase the retirement benefit by 8% per year after full retirement age until age 70. Someone with a full retirement age of 67 who waits until 70 generally receives about 124% of the full-retirement-age benefit before subsequent cost-of-living adjustments.
That does not mean everyone expecting a long life should automatically wait until 70. Health, spouse and survivor considerations, cash flow, pensions, and the amount you would need to withdraw from investments while waiting all matter.
RetireNova’s guide to Social Security benefits and future payout considerations can help place the claiming decision within a broader retirement plan.
Step 5: Do Not Treat the 4% Rule as a Guarantee
Rules of thumb can help begin a retirement conversation, but a retirement potentially lasting to age 100 deserves more than one fixed percentage.
The familiar 4% approach is commonly used as a starting reference for portfolio withdrawals. For example, 4% of a $1 million portfolio would equal $40,000 during the first year before considering how future withdrawals are adjusted.
That does not mean $40,000 is automatically sustainable for every retiree for 35 or 40 years.
Retirement age, asset allocation, inflation, investment returns, taxes, pensions, Social Security, spending flexibility, and market conditions early in retirement can all change the result.
Instead of asking whether one withdrawal rate is “safe,” test several withdrawal strategies and determine how much flexibility you would have after a difficult market period. A retirement income and withdrawal plan can help coordinate spending with income sources over different phases of retirement.
Step 6: Protect Against Sequence-of-Returns Risk
Living longer increases the importance of maintaining growth, but withdrawing from a portfolio also makes early market losses particularly important.
Suppose markets fall significantly during the first few years of retirement. If you continue selling the same amount of investments during the decline, you may need to sell more shares at lower prices, leaving fewer assets available for the eventual recovery.
This is sequence-of-returns risk, and it can affect two retirees with identical long-term average investment returns very differently depending on when the poor years occur.
The answer is not necessarily to move everything into low-risk assets. A potentially 35-year retirement may still require long-term growth to help offset inflation.
Instead, consider maintaining enough near-term liquidity, diversifying the portfolio, and retaining flexibility in discretionary withdrawals so poor markets do not automatically force large sales from long-term assets.
Step 7: Plan for Healthcare and Long-Term Care Separately
Healthcare is one of the areas where a very long retirement can differ substantially from a typical 20-year projection.
Medicare provides important health coverage beginning around age 65 for most retirees, but it does not cover every healthcare expense. More importantly, Medicare generally does not pay for most long-term custodial care when that is the only type of care someone needs.
That means a plan extending to age 95 or 100 should consider how later-life care might be funded. Possible resources could include personal assets, long-term care insurance where appropriate, family support, home equity, or Medicaid for people who meet applicable eligibility requirements.
You do not need to assume that years of expensive care will definitely occur. The goal is to understand what resources would be available if health or mobility changes substantially in your 80s or 90s.
Step 8: Keep Enough Growth for a Multi-Decade Retirement
The word “retirement” can make an investor feel that the portfolio suddenly needs to become extremely conservative. For someone who may live another 30 or 35 years, that can create its own risk.
Inflation compounds over long periods, reducing the purchasing power of cash and fixed payments. A portfolio designed only for stability may therefore struggle to support the same lifestyle decades later.
Your investment allocation should balance shorter-term spending needs with the need for longer-term growth. Money needed within the next few years can be managed differently from assets that may not be used until your 80s or 90s.
A bucket-style approach can provide one framework, with near-term assets emphasizing liquidity, intermediate assets balancing stability and growth, and longer-term assets having more time to remain invested.
The exact allocation should reflect your income sources, spending needs, risk tolerance, and financial capacity rather than a universal age-based formula.
Step 9: Think About Taxes Over Decades, Not One Year
A long retirement can contain several very different tax phases.
The years immediately after employment ends may involve relatively low taxable income. Later, Social Security, pensions, required minimum distributions, and investment income can change the picture.
That creates opportunities to plan rather than simply reacting to taxes as they occur. In some lower-income years, planned traditional retirement-account withdrawals or Roth conversions may help manage the size of future tax-deferred balances.
Required minimum distributions are another reason to think ahead. The applicable RMD age depends on birth year, generally 73 for some current retirees and 75 for people born in 1960 or later.
If you want a deeper explanation of how those mandatory withdrawals work, RetireNova’s guide to required minimum distributions and the rules by age can help you plan for that later stage of retirement.
The objective should be managing lifetime taxes while maintaining adequate spending flexibility, not simply paying the smallest possible tax bill this year.
Step 10: Keep Home Equity and Other Assets in the Backup Plan
For many retirees, the home is one of their largest assets but is not initially part of the retirement-income portfolio.
A plan extending to age 100 should at least consider what role that equity could play later. Downsizing could reduce housing expenses and release capital, while a reverse mortgage may be an option for some qualifying homeowners after evaluating the costs and terms.
The important point is not that everyone should use home equity. It is that an asset representing a substantial part of household wealth should not be ignored when modeling a very long retirement.
Other resources, such as insurance, business interests, rental property, or an inheritance, should also be evaluated realistically rather than assumed to solve a future shortfall automatically.
Step 11: Plan for a Surviving Spouse, Not Just Two Lives Together
Longevity planning for couples needs an additional layer because one spouse may live considerably longer than the other.
Household expenses often decline after one spouse dies, but they do not usually fall by half. Housing, utilities, property taxes, and many other fixed costs remain, while one Social Security benefit may disappear and the household may move from a joint to a single tax filing status.
Pension survivor elections can also affect income available to the surviving spouse.
A strong retirement plan should therefore test not only whether both spouses can reach 95 or 100 together, but whether either spouse would remain financially secure for many years after the other dies.
Step 12: Revisit Longevity Assumptions Every Year
Planning to age 100 does not mean creating one 35-year projection and following it unchanged.
As you age, uncertainty changes. Your health, spending, family situation, investments, tax law, housing, and priorities may all look different five or ten years later.
An annual review can update retirement spending, investment withdrawals, Social Security decisions, RMD planning, healthcare costs, and estate goals. Major changes such as widowhood, illness, relocation, or a substantial market decline should prompt an additional review.
A retirement dress rehearsal can also help before retirement begins by testing how your projected spending and income work together while you still have time to adjust.
Planning to 100 Is About Flexibility, Not Fear
A retirement plan does not need to assume that you will definitely live to 100. It does need to consider what would happen if retirement lasts substantially longer than average.
Someone retiring at 65 could potentially need income for 35 years. Over that period, markets will change, inflation will compound, healthcare needs may evolve, tax rules may shift, and the lifestyle you want at 75 may look very different from the one you want at 95.
The strongest response is not simply to spend less forever. It is to build a retirement with multiple income sources, enough long-term growth, thoughtful withdrawal decisions, healthcare planning, and flexibility to adjust as circumstances change.
Longevity should therefore be treated as a planning scenario rather than a prediction. If your plan remains resilient through age 95 or 100, you are less dependent on correctly guessing how long retirement will last.
Frequently Asked Questions
Should I plan as though I will live to 100?
Age 100 can be a useful stress-test even though it is well beyond average life expectancy. Testing a longer lifespan helps reveal whether your income and investment strategy would remain flexible if you live substantially longer than expected.
What is life expectancy for someone who reaches age 65?
Social Security’s 2026 projections show period life expectancy at age 65 of about another 18.4 years for men and 20.9 years for women. These are averages, which means individual outcomes can be substantially shorter or longer.
Does a longer retirement mean I need a much larger portfolio?
Potentially, but portfolio size is only one part of the equation. Pensions, Social Security, housing, spending flexibility, taxes, retirement age, investment returns, and other income sources all affect how much investment wealth is needed.
Is the 25-times-expenses rule enough for a 35-year retirement?
It can provide a rough starting reference, but it should not be treated as a guarantee. A long retirement should be tested against different investment returns, inflation rates, spending patterns, healthcare needs, and withdrawal strategies.
Does delaying Social Security help with longevity risk?
Potentially. Delaying after full retirement age increases the monthly retirement benefit until age 70, giving you more lifetime income if you live longer. Whether delaying is appropriate depends on the rest of your financial and personal circumstances.
Does Medicare cover long-term care?
Generally, Medicare does not cover long-term custodial care when that is the only care needed. A long retirement plan should therefore consider how later-life support or long-term care could be funded.
Should I invest more conservatively if I might live to 100?
Not necessarily. A longer time horizon can increase the need for long-term growth as well as stability. The appropriate investment mix should consider your spending, guaranteed income, risk tolerance, and how soon different assets will be needed.
How often should I update a longevity plan?
Review it at least annually and after major changes involving health, family, housing, income, taxes, or investments. As retirement progresses, assumptions can be replaced with better information about your actual spending and circumstances.
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