Why continuity affects quality
A cleaner who attends the same site each week learns things no schedule captures: which door sticks, where the spare liners are kept, that the meeting room is used on Tuesdays, that the third washroom dispenser empties fastest. That accumulated knowledge is why a settled cleaner produces better results in the same hours. Constant rotation resets it, and the site experiences that as a decline in standards even though nothing in the schedule changed.
Continuity also matters for security. In premises where the cleaner works alone with access to the whole site, a familiar person is easier to trust and easier to hold accountable. Sites with vulnerable occupants or confidential material have a stronger interest again. None of this requires an unreasonable demand; it requires the scope to state that continuity is expected and that changes will be notified rather than simply happening.
