Software Architect's Handbook

Law V – Conservation of familiarity

As a software system evolves, the group of individuals who are working on it must maintain the same level of familiarity with the system so that it can evolve without compromising the quality of the system. If we want the ability to handle whatever forces of change might affect the software system and make modifications in an efficient way, we have to maintain a deep understanding of the system.

Too much growth can decrease the level of familiarity as it becomes increasingly difficult to maintain the same level of knowledge over the technical and functional aspects of the system. For this reason, it is ideal if, during the lifetime of a software system, the amount of change in each release remains roughly ...