A retirement plan rarely collapses because someone buys one too many cups of coffee. The bigger threats usually arrive quietly: a market downturn early in retirement, an unexpected health expense, inflation that refuses to behave, or a spending habit that looks harmless until it gets multiplied across decades. The uncomfortable question is not simply whether there is enough money saved, but what happens when the plan encounters something it never expected.
That makes stress-testing a retirement plan far more useful than admiring a projected account balance on a spreadsheet. A plan can look perfectly healthy under ideal conditions and still wobble when several ordinary problems arrive at the same time. The goal is not to predict every twist in the future, because nobody gets that superpower, but to identify the weak spots before retirement puts them under pressure.
