One of the most important things marketers know: Selling to existing customers is much less expensive than attracting new customers. Why haven't cell phone companies picked up on this yet? They spend all their money giving new phones and cheap plans and specials to attract new customers. Yet they do nothing to keep their current customers happy. Because of this, they lose all their current customers, who switch to a different company every few years because of "new customer incentives." Maybe cell phone companies should change their focus and try to maintain current customers and decrease their marketing/promotions budget.