Store the rhythm, not just the order. A standing Tuesday delivery is the most profitable thing a corporate caterer has, and it survives only if skipped weeks, holiday shutdowns and headcount changes can be handled without rebuilding the whole thing by email each time.
Fix the change deadline in writing and price what happens after it. Five cancelled portions on the morning are food already bought and staff already rostered, and without an agreed cut-off the kitchen absorbs that difference every single week.
Track what goes out and what comes back per client. Trays, urns and reusable containers vanish across a quarter without anyone noticing, and replacing them is a cost nobody ever quotes for.