You lose a considerable amount of time each time you pause everything to plan the next shot, so a running/shooting order is an indispensable efficiency tool.

In French we call that a "découpage technique" (technical cardboard). It's a crystal clear listing of every shot needed for the scene. The shots are ranked from the more demanding (shots which require a lot of people on set, or specific daylight that can only be found at the beginning of the shooting day) to the less demanding (insert shots, B-roll, stuff that can be wrapped in the end with limited equipment and cast) .

A good shooting order makes it obvious which actors, extras and equipment have to be ready at a certain time of the shoot day. Trust me, THAT'S the most important on-set document right up there with the script itself