How To Know If You Have Product-Market Fit (And Why Most Frameworks Get It Wrong)

Sean Ellis calibrated his 40% benchmark on Dropbox, Eventbrite, and LogMeIn — consumer products with short feedback loops in 2009. Applying it to European enterprise B2B today, to hardware with nine-month sales cycles, or to developer tools with free tiers produces results that are at best approximate and at worst actively misleading. Not because the framework is wrong, but because PMF is category-specific. Real product-market fit is behavioural: customers restructure their workflow to accommodate your product, resist churn when you introduce friction, and expand without a discount to incentivise them. Those things don't show up in surveys. They show up in retention curves, net revenue retention, and how people respond when you threaten to take the product away.