In systems architecture, there are rarely any right answers – mostly just trade offs between one solution or another. In such cases it helps to bear in mind some fundamental principles as a guideline. One principle I often use is cost vs. benefit. Another useful principle is to minimize coupling between systems. Coupling is pervasive and leads to a kind of inertia in enterprise systems. Newton discovered that inertia prevents change and if there is one thing that enterprises struggle most with, it’s change.