Throw out sunk cost when the market speaks - 2 years of work can become irrelevant overnight
One of the hardest founder decisions is abandoning work you've invested years building. But clinging to sunk cost prevents you from building what the market actually wants. When you discover that the core assumption underlying your product is wrong, iterating on the edges won't fix it—you need to rebuild from scratch. TeamBridge spent 2 years building a scheduling tool that failed, then threw it out entirely to build composable Legos. The new direction outsold 2 years of work in the first month. The lesson: sunk cost is only a fallacy if you let it trap you. The market doesn't care how much time you invested in the wrong solution. Your willingness to throw out prior work is often the unlock to finding product-market fit.
When to use
When you've invested significant time (months or years) building a product but the market isn't responding despite sales effort and product iterations. When you discover through customer feedback that your core assumption is wrong—not a feature gap, but a fundamental misunderstanding of the pain. When continuing to iterate feels like pushing a boulder uphill. Best for founders who have built enough to learn but need permission to pivot dramatically.
Don't do this
Continuing to iterate on a fundamentally flawed product because 'we've already built so much.' Treating time invested as justification for further investment. Viewing a pivot as failure rather than as applied learning. Making small tweaks when the market is telling you the core concept is wrong.
1 Founder Who Did This
Threw out 2 years of scheduling product work when market clearly spoke, rather than iterating on failing approach