A cushion lets you live through a surprise without selling at the worst moment.
Leave room for error.
Your costs are €2,000 a month. Pull the line up to the cash you keep aside.
Room for error keeps a bad month a bad month, not a loan.
← Red LinesRed Line 6 of 48 The idea The numbers Why it matters Where it bends This game’s numbersHow strong the proof isBGood proof, with limits Where it comes from
Plans assume things go roughly to plan. They rarely do. Room for error is the part of the plan that expects the surprise.
Costs are €1,500 a month. In March markets fall 30%. In May pay stops for two months and the car needs €800: €3,800 to find. Two months of cushion is €800 short; three months is enough.
Without the cushion, the €800 comes from selling shares just after a 30% fall. A dip you could wait out becomes a loss for good.
A cushion far too big loses quietly to inflation. Three to six months of costs is the usual size.
Eurostat: one in three unable to face unexpected expenses (2020)The year and the buffer: worked out on this page
Households with emergency savings face less hardship after a shock, but the studies follow households over time rather than test it, and are mostly from the US.
- Emergency Saving and Household Hardship Leah Gjertson, Journal of Family and Economic Issues 37(1), 1-17, 2016
Checked 2 Nov 2026 · How we grade
- A Strong proof: Many good studies or long official data, from different teams or countries, point the same way.
- B Good proof, with limits: Solid studies agree on the direction, but the size varies, or the data covers few places or few kinds of people.
- C Mixed proof: Some good studies for, some against, or the evidence covers only part of the line.
- D Thin proof: Mostly one book’s argument, one survey or stories. It may be wise, but it has not been tested well.
- = True by the sums: It follows from arithmetic, so no study can overturn it. We still show what real data says.
Morgan Housel, The Psychology of Money (2020). In our words, not quoted.
See it in numbers: Cushion (From Zero)
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