Expressive Power

One of the abstractions I have found most useful in software design is that of "expressive power." Whether designing a simple script or a complete software system, I always keep in mind some idea of the scope of data to be stored and communicated.

I may not always know exactly how the system will be used, but if in my initial development I can provide the users with the ability to store and relate the data that they need, the design should be sufficient for the application This is the idea behind expressive power; not "have I implemented every function the user may ever want," but "have I provided the hooks, storage and structures that are able to contain all the functions the user may want."

If my system provides the latter, then I will be able to evolve and expand it as my users desire without having to redesign large segments of the architecture or data storage methods.

So, provide a system whose "language" is expressive enough to meet their future needs, giving room for the addition of features in an evolutionary and controlled manner. You and your users will appreciate it!