What is the role and purpose of design patterns in software development?

Design patterns are proven solutions to common software design problems. Their roles and purposes include:

• Providing standardized and understandable ways to solve frequently encountered problems.
• Improving the quality and maintainability of code.
• Simplifying communication among developers, as patterns have generally accepted names and descriptions.
• Helping to avoid reinvention of the wheel.

For example, the "Singleton" pattern guarantees that a class has only one instance, and the "Factory" pattern simplifies object creation without tight coupling to specific classes.