Most knife services in the US charge $1 per knife and come once a week. They use cheap stainless steel knives that can be whittled down, but the edges only hold up for a few hours of work(esp with nylon cutting boards.) They have duplicate sets of whatever knives they provide so they come in with a fresh set of sharp knives and then trade out the used ones to be sharpened during the week. A typical restaurant will have 10-20 knives in rotation and they service a hundred or more restaurants per territory. It ends up being a nice little business. Nothing makes line cooks quite so happy as when the knife guy comes..
Linen services charge 25-50 cents per item and they wash and fold the napkins, kitchen towels, aprons, and often uniforms. But it's brutal work lugging sacks of wet laundry around that typically weigh at least 50 pounds per restaurant. A 1000 napkins a week in a busy restaurant and you get into serious money.
