IDEA FOUND // IDEA 18

Mind & biases4 MINGuided readEstablished evidence

Sunk-Cost Effect

The ticket is paid for and the play is dull. How much of that money can your next hour recover?

01 / PLAINLY

What it means, plainly

A cost that is already spent and cannot be recovered can push people to continue even when it will not improve what happens next.

02 / CONTEXT

A little more

A sunk cost cannot be recovered, yet it can keep shaping later choices. People persist to avoid feeling that time, effort, or money was wasted even when continuing worsens future outcomes.

03 / WHY IT MATTERS

Why it matters

Treating past loss as a reason to continue can consume more time or money and crowd out better alternatives.

04 / EXAMPLE

A familiar example

A team keeps an unworkable project alive because it already spent six months on it, although a new option promises better results from now on.

05 / LIMIT

What it does not mean

Quitting is not always wise; past investment may reveal information or build capabilities that genuinely alter future returns.

06 / NOTICE

Notice it in your day

Split a page into “continue” and “stop.” List only future consequences on each side, and place everything unrecoverable in a separate box.

FINAL NOTE

The idea worth keeping

Compare only the costs and benefits each option can produce from this point forward.

QUESTIONS / 02

Questions people still have

Why is it hard to leave something already paid for?

Continuing can feel like a way to keep the cost from being wasted, even though it cannot recover that cost.

Should past investment never enter the decision?

It can matter if it produced information or abilities that change future returns, but not merely because the cost was incurred.

RESOURCES / 01

Sources you can check

These links show where the explanation comes from. Some are academic and may be more technical.

Editorial review: 2026-08-14

PATHS / 03

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If this idea raised another question, continue along one of these paths.