FIFO stands for First-In, First-Out, meaning that inventory items are used in the order of the oldest to the newest, in an effort to ensure that inventory products do not expire before being used. This system also helps to ensure the average shelf life of the inventory remains as high as possible.
This is analogous to the behavior of persons standing in a line, where the individuals leave the queue in the order they arrive, or waiting one’s turn at a traffic signal.
Sources: Wikipedia, RSOPerator.
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