Retention refers to the ability of a business to keep its customers over time. The opposite of retention, then, is attrition—the process by which customers leave and are not replaced in a timely manner. Attrition can be caused by a loss of interest in the product or service offered by the company, pricing that’s too high for customers to maintain, or a lack of customer engagement from the company itself. Attrition can lead to diminishing sales and declining profits if it’s not managed properly and if customers aren’t adequately retained and replaced.