Final answer:
Refactoring is constantly used during XP development to improve the design of the software and reduce technical debt.
Step-by-step explanation:
Refactoring is constantly used during XP (Extreme Programming) development because it helps improve the design of the software. Refactoring involves making changes to the code without changing its external behavior, making it easier to understand and maintain.
XP follows a spiral design process, where changes are made in the design and then evaluated. Refactoring allows developers to continually improve the design during each loop of the spiral, leading to a better end design.
By refactoring regularly, developers can keep the code clean and reduce technical debt. It helps identify and fix issues early, improves the code's readability, and makes it easier to add new features or make changes in the future.