For the non-guerrilla sales person, following up, what we call "tracking," is done rarely and then only superficially. Once they have won, sales people want to move on to the next battle. There's little interest in a long-term relationship. Studies consistently show that selling to repeat customer a much cheaper and infinitely easier operation than finding new customers. The most efficient sell is reselling current customers on products and services that they've purchased in the past. The second most efficient sell is new products to old customers. Follow up within 30 days of the last sale.