A building site clean is not one clean, it is three, and anybody who tells you otherwise has not done one.
The first pass takes out the bulk and the loose dust. The second, a day later, takes the fine dust that settled out of the air after the first. The third catches the tracks, the grilles and the window channels where plaster dust hides and from where it keeps reappearing for weeks.
We price all three together and we do not offer one on its own for a place that has just had plastering or tiling done, because a customer who buys one pass will fairly conclude that we did a bad job.