An important part of stock control is to keep an inventory of stock levels, and to reorder and replace stock that has been sold to customers. Nowadays, most stock control is automated by a computer system, being linked directly to the tills, with the tills being linked to stock levels available in the warehouse, and even in other branches if need be.
Most businesses hold an annual stocktake, which is usually done manually by employees visually noting and counting stock levels, which are then used to update and correct the computer system. The annual (once or twice yearly) stocktake is also done for insurance purposes, and to bring to light any misplaced, missing or stolen stock.