Peak weeks are known a year in advance
The advantage of an academic calendar is that it is published a long way ahead and rarely moves. Enrolment periods, orientation, the first fortnight of each semester, examination weeks and graduation are all fixed dates rather than surprises, which means the cleaning schedule can carry the adjustment before the pressure arrives rather than responding to it two weeks afterwards when somebody complains about the state of the counter.
Those weeks affect the office in a fairly specific way. Counter and enquiry traffic rises sharply, waiting areas fill and stay full, washrooms take much heavier use than usual and waste volumes climb. The appropriate response is usually a daytime pass rather than a longer evening attendance, because the problem is accumulation during the day in public-facing areas rather than insufficient time to work overnight.
