Three different things arriving in identical words
The corridor on level six is dirty. That sentence could mean the scheduled clean did not happen, that it happened and the frequency is insufficient for the traffic, or that the resident expects something the scope never included, such as carpet spot cleaning between periodic extractions. Those are three different problems with three different solutions, and without an inspection they are indistinguishable. Adding a fourth possibility, that the area was cleaned and then used heavily within the hour, accounts for a surprising share of corridor complaints in large buildings.
That is why the inspection field matters more than any other. A supervisor checking the area and recording what was found converts an assertion into a fact, and the fact usually points directly at the solution. It also protects both parties: the contractor from a complaint about something outside the scope, and the residents from a service that genuinely is not being delivered.
