Soil travels, and the route decides where
On a site with a warehouse component, the dust and debris in the storage area is different in kind from office soil and it moves easily on wheels and footwear. A crew that works the warehouse and then the offices carries that material into carpet and onto desks, and the result is an office that looks worse after cleaning than before. Working the reverse direction removes the problem entirely at no cost.
Equipment is changed at the boundary rather than carried through, which is the other half of the same principle. The vacuum used on a warehouse floor does not go onto office carpet. Cloths do not travel from a dock area to a meeting room. Setting those boundaries physically, with staged equipment, is far more reliable than expecting the crew to remember the rule at eleven at night.
