FIFO and LIFO
FIFO and LIFO are used in the management of inventory flow. FIFO (First In First Out) means that inventory is picked off the shelf in the order it was received. LIFO (Last In Last Out) means that last items received into the warehouse are always the first to be shipped out.
FIFO is the most common inventory control method in order fulfillment. Specifically with lot-controlled food products, clients would like to keep their inventory current and fresh and ensure that older items on the shelf are the first to ship out.
FIFO and LIFO are not as important for non-food based products since one shipment of a widget is likely identical to another.