Days of inventory is a measure used by production management teams. It is calculated by dividing inventory on hand by average daily inventory usage. The result is an initial estimate of the number of days production could continue using just materials on hand. Further insights can be obtained by looking at specific types of inventory (raw-materials inventory, work-in-process inventory, and finished-goods inventory).
Glossary
Days sales outstanding
Days sales outstanding (DSO) measures the speed at which a company collects accounts receivable from those who owe it money. Some companies may have 40 DSO, while others have created ways to collect money almost immediately on shipment of the product, and others may not be paid for months by customers.