How often should I calculate prime cost — and who should own it?

Weekly, on the same day every week, from five inputs: purchases, opening and closing inventory, sales, labour hours and rates, with overtime flagged separately. The head chef owns the food inputs, the manager owns the labour inputs, and the owner reads the one number beside last week's. Once the sheet exists it takes well under an hour — and it catches in week two what a month-end read discovers after four weeks of leak.

From Restaurant Prime Cost: The 60–65% Ceiling That Decides Survival — the full reading, with the method behind this answer.