Illinois Inventory is a system used to track goods and materials within a business. It can help businesses keep track of the quantity, location, and condition of their inventory, as well as the associated costs. The system can be used to ensure the accurate and timely replenishment of stock and materials, and to provide insight into the cost of goods. There are three types of Illinois Inventory: perpetual inventory, periodic inventory, and cycle counting. Perpetual inventory is a system in which inventory levels are continuously monitored and updated in real time. Periodic inventory is a system in which inventory levels are tracked and updated at predetermined intervals. Cycle counting is a system in which inventory is counted periodically in order to verify accuracy and ensure that inventory levels are accurate.