episodes. The relationship can terminate if: the customer moves away from the company's service area, the customer no longer has a need for the company's products or services, more suitable alternative providers become available, the relationship strength has weakened, the company handles a critical episode poorly, unexplainable change of price of the service provided. The final link in the model is the effect of customer loyalty on profitability. The fundamental assumption of all the loyalty models is that keeping existing customers is less expensive than acquiring new ones. It is claimed by Reichheld and Sasser (1990) that a 5% improvement in customer retention can cause an increase in profitability between 25% and 85% (in terms of net present value) depending upon the industry. However, Carrol and Reichheld (1992) dispute these calculations, claiming that they result from faulty cross-sectional analysis. According to Buchanan and Gilles (1990), the increased profitability associated with customer retention efforts occurs because: The cost of acquisition occurs only at the beginning of a relationship: the longer the relationship, the lower the amortized cost. Account maintenance costs decline as a percentage of total costs (or as a percentage of revenue). Long term customers tend to be less inclined to switch and also tend to be less price sensitive. This can result in stable unit sales volume and increases in sales volume. Long term customers may initiate free word of mouth promotions and referrals. Long term customers are more likely to purchase ancillary products and high-margin supplemental products. Long term customers tend to be satisfied with their relationship with the company and are less likely to switch to competitors, making market entry or competitors' market share gains difficult. Regular customers tend to be less expensive to service because they are familiar with the processes involved, require less "education," and are consistent in their order placement. Increased customer retention and loyalty makes the employees' jobs easier and more satisfying. In turn, happy employees feed back into higher customer satisfaction in a virtuous circle. For this final link to hold, the relationship must be profitable. Striving to maintain the loyalty of unprofitable customers is not a viable business model. That is why it is important for marketers to assess the profitability of each of its clients (or types of clients), and terminate those relationships that are not profitable. In order to do this, each customer's "relationship costs" are compared to their