The fixed costs inside every visit
Travel to the site, parking, entering the building, collecting equipment, setting up, packing down and securing the premises all take time and none of it produces cleaning. In a large building these costs are spread across several productive hours and barely register. In a small suite they can represent a substantial share of the attendance, which is why providers set a minimum below which a visit is not viable at any sensible rate.
This is not a matter of a provider being unwilling to do small jobs. It is arithmetic, and every reputable contractor faces the same constraint. Understanding it changes the conversation from trying to negotiate below the floor, which rarely works and sometimes produces a rushed service, to deciding how to use the time that is being paid for regardless. Asking each provider to state the minimum openly makes the constraint visible rather than hidden in a figure.
