The inside sales force can be used to replace direct contact for marginally profitable customers. A general rule of thumb in business says that 20 percent of customers account for 80 percent of sales, so conversely the remaining 80 percent of customers generate just 20 percent of sales. But businesses must keep in mind that marginal does not necessarily mean unprofitable. And the existing customer base is perhaps the most important asset in any business; sales increases most often come from current accounts, and it generally is less costly to maintain current customers than to search out new business. Telemarketers can give these reliable customers the attention they deserve. The reps can phone as often as needed, determine the customers' purchasing cycles, and contact them at appropriate reorder times.