Code Reusability refers to the practice of using existing code for new functions or applications instead of writing new code from scratch. This approach saves time and effort, as developers can leverage previously tested and proven code, reducing the likelihood of errors and bugs. It promotes efficiency and consistency across projects. By implementing modular programming techniques, developers can create reusable components or libraries that can be easily integrated into different programs. This not only speeds up the development process but also enhances maintainability, as updates to reusable code can automatically benefit all applications that utilize it.