A warehouse stores things, and that changes the problem. There are few people and few air units for a very large volume, the ducts often run at great height above the shelving, and the loading docks open and close with every truck. What comes in through those doors, yard dust included, can reach the filters and the returns.
So the emphasis is on access and on the movement of goods. Before cleaning, it is checked which sections can be reached from the floor, which need a platform or a ladder, and what load sits underneath. If the load cannot be moved, it is protected or the work goes section by section.
Data point: A modeling study by Waring and Siegel (2008) estimated that filters in commercial systems collect a median of 130 g/m² per month, compared with 2.97 in residential ones. It is an estimate, which is why the actual case is inspected.