Difference in Items Ordered and Items Purchased Fields in Customer Saved Search

Navigate to Lists > Search > Saved Searches > New > Customer

Under the Criteria tab > Standard subtab, you may select Items Ordered or Items Purchased

Items Ordered are items which customers ordered via Sales Orders. These items may not be considered "purchased" unless the Sales Order is billed.

Items Purchased are items which customers bought. These items are from Invoice and Cash Sale transactions.