Here’s an interesting quote from Kent Beck. He says:
The product of software development is two-fold:
• The behavior of the system
• The options for extending and modifying that behavior in the future.
That second point summarizes what good software design is about. Each feature we build in our code gets us closer to release. But the way we build each feature can set us on different paths. If we don’t care how it works, as long as it works, then our launch may come and go without a problem. But when it’s time to return to that feature and make a change or an improvement, we’ll likely find ourselves wading through a tangle of spaghetti.
We want to take the other path, where each coding decision carries a question with it: What will I think of this code when I need to change it in six months? Will I understand it? Will changing this break other things, or will the change be isolated? This habit, to the extent that we can keep it up, allows us to keep improving our apps instead of getting stuck in spaghetti.