SOLID Design Principles Explained: Write Code That Scales Without Breaking

SOLID is a set of five software design principles aimed at making codebases easier to change and maintain as they grow. The Single Responsibility Principle states that each class or method should have only one reason to change, reducing unintended side effects. The Open/Closed Principle requires that code be open for extension but closed for modification, so new features can be added without altering existing, working logic. These principles are illustrated using Python examples involving bird classes, showing how poor design leads to repeated edits and regression risks. The article also highlights that composition is generally safer than inheritance in larger teams, as it avoids tight coupling across class hierarchies.