Why one long visit under-serves a large workforce
An amenities block used by a large workforce reaches its worst condition well before the end of the day. A single attendance at the close of the shift means the block is at its best when nobody is there to use it and at its worst during the afternoon, which is precisely backwards. The total hours may be adequate; the placement is not.
The same applies to a crib room. It takes its heaviest use at the main meal break and then sits until the following day if the only attendance is in the evening. A room serviced immediately after the break is available and presentable for the rest of the shift, which is a materially different outcome from the same work performed six hours later.
