How much inventory should I be buying for a store the size of mine? Buying inventory is easy—buying the right amount of inventory at the right time is a bigger challenge. It’s no secret that retailers in the music products industry often suffer from having too much inventory on hand. There a variety of reasons for this situation, ranging from the vast number of stock keeping units (SKUs), to vendor purchase requirements for coveted product lines. But most high inventory levels result from both a retailer’s love of product and a lack of understanding of the key tools and measurements used in effective inventory management.