The building decides most of the risk
Where the cleaner's store is located determines how far equipment is carried every shift. Where water is available determines how often a heavy bucket is moved. Where the bins are, and whether the route includes steps, a kerb or a heavy door, determines the hardest task of the night. None of those are within a contractor's control, and all of them are decided by the building.
That is why raising them is worthwhile rather than complaining. A tap installed on the second floor, a bin room door held open with a proper stay, a ramp instead of two steps, or a storage cupboard relocated closer to the work can remove a daily hazard permanently. These are usually small building decisions with a disproportionate effect on the task.
