The rule of seven touches resonated loud and clear.

This, incidentally, is why the entire "relationship selling is dead so wow the customer with your brilliant insights" concept (see "The Challenger Sale") is so ridiculously inept.  Truth: if you can't build a relationship, you won't sell anything to anybody.

Gawande's pharmaceutical rep was a believer in the old sales theory of "the rule of seven touches," where you have to "touch" the customer seven times, so that they know you, might trust you, and trusting you, might try (or buy) something different...from you.

Seven is a LOT of touches but it makes sense.

That's how long a relationship takes to progress to the point of trust.