Product-market fit isn't just growth; it's an extreme market pull where customers buy your product despite its imperfections. The ultimate signal is when deals close quickly and repeatedly, with users happily ignoring missing features because the core value proposition is so urgent and compelling.

Don't treat validation as a one-off task before development. The most successful products maintain a constant feedback loop with users to adapt to changing needs, regulations, and tastes. The worst mistake is to stop listening after the initial launch, as businesses that fail to adapt ultimately fail.

Unlike traditional software where PMF is a stable milestone, in the rapidly evolving AI space, it's a "treadmill." Customer expectations and technological capabilities shift weekly, forcing even nine-figure revenue companies to constantly re-validate and recapture their market fit to survive.

Founders must distinguish between persistence and fighting a losing battle. If you constantly feel like you're pushing a boulder uphill to convince the market, you're on the wrong path. Genuine product-market fit feels like the market is pulling you, and your job is to sprint to keep up.

An internal incubator’s biggest mistake is acting like an external startup. Finding product-market fit is insufficient. Lasting success requires achieving "product-company fit" by deeply understanding and aligning with the parent company's internal business units, strategic goals, and unique challenges.

Success in startups requires nuanced thinking, not absolute rules. For instance, product-market fit isn't a simple 'yes' or 'no' checkbox; it exists on a spectrum. Learning to see these shades of gray in funding, marketing, and product strategy is a hallmark of a mature founder.