“The question I ask myself on female health is, who's the Apple of female health... the brand you go to that is by far the best and you don't question it, you just buy it — and there isn't one. There should be one for something that happens millions of times a year.”

Pick a category where there is no obvious 'Apple of X'

Consumer subscription categories tend toward a duopoly of two to four winners plus long-tail SMBs. The biggest validation signal is finding a category with millions of recurring users and no default brand answer: femtech, family management, youth sports coordination, private wealth between Wealthfront and Goldman. Those gaps are the category-killer opportunities.