[frankc]

I love this book but yes, you really need to understand when it makes sense to apply these patterns and when not to. I think of these kinds of architectural patterns like I think of project management. They both add an overhead, and both get a bad rap because if they are used indiscriminately, you will have many cases where the overhead completely dominates any value you get from applying them. However, when used judiciously they are critical to the success of the project.

For example, if I am standing up a straight-forward calendar rest api, I am not going to have a complicated architecture. However, these kinds of patterns, especially an adherence to a ports and adapters architecture, has been critical for me in building trading systems that are easy to switch between simulation and production modes seamlessly. In those cases I am really sure I will need to easily unplug simulators with real trading engines, or historical event feeds with real-time feeds, and its necessary that the business logic have not dual implementations to keep in sync.