DRY (Don't Repeat Yourself) is a software development principle that encourages developers to write code that is modular, reusable, and easy to maintain. The goal of this principle is to reduce the amount of duplication that occurs in software development, making it easier for developers to focus on building great applications. By writing code in a DRY way, developers can save time and energy while creating a more maintainable and secure codebase. Furthermore, DRY code is easier to read and understand, thus helping developers collaborate more effectively. Ultimately, DRY is an invaluable tool for developers who want to write code that is both efficient and robust.