The Longevity Question

How long does your money actually need to last?

It's not a question most people love sitting with. But it's one of the most useful questions in retirement planning — not because it's morbid, but because it changes how everything else gets built.

When you were working, your paycheck didn't need to last a specific number of years. It just needed to keep showing up. Retirement is different. At some point, you (and if you're married, both of you) stop adding to your savings and start asking them to hold up for however long retirement turns out to last — and nobody gets that number in advance.

That's the longevity question: not "how much did I save," but "how long does this need to work?"

Why "average" isn't the number to plan around

According to the Social Security Administration's own period life table, a 65-year-old man today has an average of about 18 more years ahead of him, and a 65-year-old woman about 21 more years. That puts an average 65-year-old's retirement somewhere in the neighborhood of two decades.

Here's the part that matters more than the average: half of all 65-year-olds will live longer than that. Retirement planning that only accounts for the average leaves the healthier-than-average half — which is a lot of people — without a plan for their actual retirement.

For a married couple, the number to think about isn't either spouse's individual life expectancy. It's the length of time until the second spouse is gone — and that's typically longer than either person's own number, sometimes by a decade or more.

None of this is a prediction about your own retirement. It's simply why "plan for the average" and "plan for what could actually happen" tend to produce two different retirements.

It's not just about running out of money

When people hear "longevity risk," they often think only about savings lasting long enough. That's part of it — but not the whole picture.

A longer retirement also means:

• More years where inflation can quietly erode what your income buys (a topic covered in its own lesson)
• More potential market ups and downs along the way, not just at the start
• More years where health and care needs can change
• More years the surviving spouse may need to manage income and expenses alone

A 20-year retirement and a 30-year retirement aren't the same plan stretched further. They can call for different decisions about income, growth, and protection along the way.

You don't need to predict the number — you need a plan that isn't afraid of it

Nobody can tell you exactly how long your retirement will last. That uncertainty is exactly why it's worth planning for a longer retirement rather than a shorter one. A plan built for 20 years that has to stretch to 30 is in a very different position than a plan that was built with that possibility in mind from the start.

That doesn't mean guessing at a bigger number and hoping. It means understanding which parts of your income are built to keep going no matter how long you live, which parts depend on your savings holding out, and how those pieces work together over a retirement that could last considerably longer than the average.