ChooseFI · Monday, September 14, 2026
Financial planning often overlooks the assumption of how long money needs to last in retirement. Many calculators default to age 95 or 90, which may be significantly longer than the average life expectancy. This can lead to over-saving, working longer than necessary, or underspending during prime years.
“For most retirement calculators and financial plans, the answer is surprisingly similar. They quietly assume a planning horizon that tees you into your 90s, often age 95 or potentially 90. It's built into the math. But for most of us, it's completely invisible.”
“But the fact that doesn't get Monte Carlo simulated or adjusted or examined is perhaps the most important factor. Which is the nest egg you need depends a lot on how long you're going to live.”
“So, if you're going to retire at 65, and you assume you're going to live to 95, and you need $714,000, but then you start to think, well, my family tends to live to 80. Or maybe my own health suggests I'm not going to live to 95. And maybe I only need $450,000. That's a pretty big difference.”