The short answer
Jason Lemkin's marker is that the founder closes the first batch themselves, roughly the first ten customers, because if you have not done it you will never be able to teach it or diagnose it. Then hire two reps, not one, and his reason is not redundancy, it is that with one rep you learn nothing: if they do well you still have no idea why, and if they fail you cannot tell whether it was the rep or your process. Two also surfaces things you cannot see otherwise. Lemkin's own first rep was strong at consultative deals and his second was strong at volume, and the contrast revealed segments and pricing he had been blind to. After two reps are hitting quota, usually somewhere past 1 to 2 million in annual recurring revenue, you hire a head of sales. Khadim Batti at Whatfix is a good example of the founder doing it first: 500 personalised cold emails in a month, and a first customer signed before the product was built.