Somewhere in your retirement plan, there’s an age.
It’s the age the whole plan is built to reach. The year your money has to last until, and it starts with one life expectancy assumption most people never see. Every number that matters to you: how much to set aside, when you can stop working, how much you can spend without worry. All of it hangs on that one assumption. And it affects nearly every retirement decision, whether your income comes from savings, Social Security, a pension, an annuity, or a combination of them.
For most people, that age is 90 or 95. And here’s the part worth knowing: in the large majority of plans, nobody actually chose it. It’s the factory setting.
Planning software comes with a default life expectancy already loaded in, and the large majority of advisors simply leave it where it sits. Age 95, out of the box, for nearly everyone who walks through the door. The retired marathon runner and the person managing a serious health condition get planned to the exact same finish line.
That sounds cautious. Play it safe, assume a long life, make sure the money doesn’t run out. But “cautious” and “accurate” aren’t the same thing, and the gap between them is where this quietly goes wrong.
The problem hiding in a safe-sounding number
Push the age out to 95, and everything downstream shifts in one direction. A longer life to fund means: save more, spend less, work a little longer. That’s not really advice at that point, it’s just what falls out of the assumption. Stretch the finish line and the plan tells you to run harder to reach it.
For a healthy person who really might see 95 or beyond, that’s the right protection. Living a long life is wonderful, and outliving your money late in it is one of the few true financial catastrophes in retirement. You want a cushion there.
But not everyone is that person. And this is the part almost no one talks about, because it cuts against the grain of how the whole industry thinks about longevity.
Consider someone whose health honestly points to a shorter runway. Maybe a serious diagnosis, a family history that’s played out a certain way. Now, a shorter runway doesn’t make planning simple; that person may still need to provide for a surviving spouse, cover long-term care, or prepare for an outcome better than the doctors expect. Those are real, and a good plan accounts for them. But planning that person rigidly to 95 anyway, without ever asking the question, can quietly cost them something: it tells them to underspend and defer during exactly the years the money could do the most good. Years they may not get back.
That’s the hidden cost. When a plan assumes too long a life without checking, the healthy client is fine and the other client may spend a decade unnecessarily restricting the very years that mattered most. And because they never see the assumption, they never know that’s the trade they’re making. It just feels like discipline.
So here’s the one thing to do with this: pull up your plan and find out what age it assumes. Then ask whether that age is honestly realistic for you, not for the average person, for you. If the answer is “I have no idea” or “I think it just says 95,” that’s worth a real conversation.
If that’s all you take from this, it’s enough. But if you want to understand why the flat number falls short and what a better approach looks like, read on.
Why Your Life Expectancy Assumption Isn’t a Safe Finish Line
Here’s the trap, and it catches good advisors too.
Life expectancy is an average drawn from a very wide range of possible outcomes. When a table says a 65-year-old has a life expectancy of, say, 87, that doesn’t mean 87 is the safe number to plan to. A large share of people in that group will live well past it. Many of them by years.
That’s the whole point: build a plan to reach only the average, and you’ve tested it only through roughly the typical lifespan, which leaves a substantial chance you outlive the plan. Not a certainty, and not a precise coin flip, but far more exposure than most people would knowingly accept for the one thing they can’t redo.
And this stays true even if the life expectancy number is beautifully accurate and perfectly personalized to you. A precise average is still an average. Making it more accurate doesn’t fix the problem, it just gives you a more accurate midpoint, when what you actually need is protection against living longer than the midpoint.
So the goal was never a better single age. The goal is to build the plan so it holds up across the range of ways your life could actually go; especially the long tail you can’t afford to be wrong about.
The better approach: personalize, then pressure-test
Here’s the move, and the point is not to swap 95 for some other magic number.
Start by challenging the default with real information about you. There are individualized longevity calculators: the Society of Actuaries has one, the University of Connecticut runs the Goldenson Center‘s version, and Northwestern Mutual offers a public Lifespan Calculator, among others. They take your actual factors — health, family history, lifestyle — and give you a range of ages with probabilities attached, instead of one generic guess. Studies using these tools have found that two otherwise-similar people can differ in likely lifespan by more than a decade, sometimes far more, once those individual factors are counted.
Then (and this is the part that keeps it honest) you don’t just plug in a new number and walk away. You pressure-test the plan against several reasonable horizons: a conservative long one that protects you if you outlive expectations, and others that reflect your real situation. You look at what changes for a surviving spouse, for long-term care, for the life you actually want to fund. A good plan should survive the long tail and not force needless sacrifice in the likely years. That takes judgment, not a lookup, but it starts with refusing to accept a number nobody chose.
The part that surprises people
Here’s what makes this genuinely different from “just plan for a longer life”: it cuts both ways.
For the healthy person whose real numbers run past 95, this catches something the default missed. They may need to plan longer, and now they will. More protection, exactly where it’s warranted.
But for the person whose health honestly points to a shorter runway, personalizing the picture can responsibly bring the planning age down, and with it, room to spend a little more, retire a little sooner, or simply stop squeezing a budget built for a life the odds didn’t support. Still careful about the long tail. Just careful about the right person.
That’s the whole case. The same tools were available to both, but one version looked at the actual human being in the chair, and the other read the number the computer printed. One is planning. The other is defaulting and calling it caution.
What to do today
You don’t need to overhaul anything. You need to know one number and whether it’s honest.
Open your retirement plan and find the age it’s built to reach. If it’s 95 and no one ever asked you a single question about your health, your family, or your life to land on it, that’s a default, not a plan. It’s worth finding out whether that age is realistic for you, in both directions.
It’s your money, your years, and your finish line. The least the plan can do is test the finish lines that actually fit your life.