When developers produce and maintain sub-optimal code, it becomes harder and harder to change this code as time goes on. That is because their peers will need to write code that interfaces with the suboptimal code and build clumsy interfaces or work-arounds to make the code work. As the code base grows, too many later code units rely on the functionality of this initial code. Of course, the later code can do little to increase the stability of the code and bugs multiply when simple changes are made; in short, development becomes slower and slower.