It might make sense to track sales and promotions by customer if there are a few large customers. In many cases, incentives are provided to large box stores for carrying the product and displaying the product in favorable positions. There are more incentives for stores to purchase a certain dollar volume of items as the more they purchase, the larger rebate they will receive. This happens in the golf industry as well as there is a trend for the major golf box stores to carry a large volume of inventory. As such, it is a good idea to track sales by the large customers and also any rebates and incentives.