The sunk cost fallacy is the tendency to continue an action because of prior investments (time, money, effort) rather than current or future value. The classic consumer example is keeping a subscription because you already paid for a year even if you never use it. That behavior misallocates future spending based on past outlays that cannot be recovered. The practical remedy is to separate past cost from present choice: ask whether continuing the subscription delivers value now, not whether you 'should get your money's worth' by enduring a service that won't be used. This reframing frees you to cancel without guilt and reallocates money to things with current value.

Concrete tactics to defeat sunk-cost thinking include pre-set evaluation windows (e.g., 'If I don't use this product three times in a month, cancel'), automated reminders to reassess at renewal, and a practice of listing current benefits on a two-line note: 'What I use vs. what I don't.' If a purchase was intended as an experiment, set an upfront expiration date and treat further commitment as a new decision that requires current evidence. Group decision-makers (household, team) can benefit from a rubric — objective criteria for retention such as frequency of use, cost-per-use, or measurable outcomes — so decisions aren't emotional after the fact. Over time this approach reduces wasted spending and builds a culture of forward-looking choices rather than past-justified persistence.