There is little merit in growing the customer base aimlessly. The goal must be to retain existing customers and recruit new customers that have future profi t potential or are important for other strategic purposes. Not all customers are of equal importance. Some customers may not be worth recruiting or retaining at all, for example those who have a high cost-to-serve, are debtors, late payers or promiscuous in the sense that they switch requently between suppliers. Other things being equal, a larger customer base does deliver better business performance. Similarly, as customer retention rates rise (or defection rates fall), so does the average tenure of a customer, as shown in Figure Tenure is the term used to describe the length of time a customer remains a customer. The impacts of small improvements in customer retention are hugely magnifi ed at higher levels of retention. For example, improving the customer retention rate from 75 to 80 per cent grows a...