At least not all of them at once. The awareness of quality deficits (these include bugs, lack of understandability, missing documentation, a lack of tests, and so on) seems to follow a sinus-curve like shape.
In those phases with the highest awareness, project managers and their developer teams often decide to dedicate a larger block of time exclusively to cleaning up the system and putting everything else on hold. All too often, the ambitious objective is to remove all quality deficits—in many cases without even specifying what a relevant quality deficit is.
Don’t do this!