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In Early-Scale Growth, the Dominant Cost Is Not CAC. It’s Time.

Sean Ellis · 28 Jan 2026

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  1. One of the most common mistakes I see startups make is optimizing for efficiency too early. They fixate on CAC ceilings, bid caps, and channel ROI before they have enough evidence that their growth model can actually scale. On paper, this looks disciplined. In practice, it often slows learning so much that the company burns far more money than it saves.

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