Appointment volume, not floor area, drives the interval
Two suites of identical size can put very different loads through the same washroom. A practice running fifteen-minute appointments across four consulting rooms generates far more visits than one running hour-long sessions in two rooms, and the consumable draw follows the same curve. Setting the interval from the appointment book rather than from the plan is the single change that makes most washroom schedules work.
The pattern within the day matters too. Many practices have a heavy morning block, a lighter middle and a second peak late in the afternoon. A single daytime check placed just after the morning block will do more good than one placed at a convenient midpoint, because it lands where the load has already accumulated rather than where the clock happens to be.
