Meeting customers’ expectations for personalization and customization requires flexibility. And such flexibility can provide a distinct competitive advantage — as long as costs aren’t spiraling out of control. In a study of nearly 250 manufacturers over a 10-year period (2005–2015), we found that 78% of firms had improved their ability to fill their total actual market demand but had lost control over costs. Apparently, chasing the often elusive customer came at a cost that many boards and shareholders had somehow overlooked (or had discreetly discounted). We also found that 11% of the companies studied had suffered both a decrease in their demand fulfillment percentage and an increase in their conversion costs, the labor and overhead costs incurred when converting raw materials into finished goods. Hardly a desirable position.