There are lots of programming and architecture patterns. Patterns allow to make code cleaner, reusable, maintainable, more testable & at last (but not at least) to feel the follower a real cool developer.
How do you rank these considerations? What does appeal you most when you decide to apply pattern?
I wonder how many times code reusability (especially for MVP, MVC patterns) was important? For example DAL library often shared between projects (it’s reusable) but how often controllers/views (abstracted via interfaces) are reused?
Code complexity reduction ranks high, if I keep things simple, I can maintain the project better and work on it faster to add/change features.
Reusability is a tool, one that has its uses, but not in every place. I usually refactor for reusability those components that show a clear history of identical use in more than three places. Otherwise, I risk running into the need of specialized behavior in a place or two, and end up splitting a component in a couple of more specialized ones that share a similar structure, but would be hard to understand if kept together.
Testability is not something I personally put a lot of energy in. However it derives in many cases from the reduced code complexity: if there are not a lot of dependencies and intricate code paths, there will be less dangers to break tests or make them more difficult to perform.
As for showing-off-ability… well… the customer is interested in how well the app performs in terms of what he wants from it, not in terms of how “cool” my code is. ’nuff said