How many? What, cooks? Waiters? Bartenders? "Grunts" who load and unload heavy equipment from the van to the site? 8 Hrs before any function starts, 90% of the food is done. Period. It has to be, or I wouldn't sleep, and I'd be holy terror to whomever stands in my kitchen. Yeah sure, meat is cooked/roasted just before the event, but all the prep is done loong in advance. Same with the packing. Everything is packed a day before: Chafers, sterno, cutting station stuff, chinaware, and a checklist with "loaded" and "returned" columns. Oh, and CLEAR plastic bags for the soiled linens.......
A Chef has got to work with his "gas gauge" and his "speedometer", that is, his labour cost and his food cost. By the time any Chef has finished reading through a new-never seen-before-function sheet, his brain is already ticking like a time bomb: What to order, what to piggyback with other orders, what to pull from the freezer, what cooks to call, what menu items are similar and can be done in conjuction with other events, what projects to put on hold, or what projects to expedite. Usually done in 1/100th of second.
Time: If you have enough of it, it's your best friend, better than a gift of a free Porsche with a supermodel in the passenger seat and the glove compartment full of unmarked $100.00's. Time, your worst enemy if you don't have enough of it, worse than being chained to the couch with your eyelids taped open and Bawbwa Streisand's "Yentl" video torturing you....