As in our real life (or in daily life) we have some pattern to live in better way like doing yoga, exercise, watching movies, playing games etc. Whereas we don't know at initailly that how yoga/exercise is going to be benifitial to us but since we find many people who are living in better way by doing yoga/exercise (and many other things) it will definitely benificial to use also. So yoga/exercise is methodologies for solving general problems .

So in same way, design patterns provide access to proven methodologies for solving general problems and the ability to use the collective knowledge and experience of the IT community to improve the quality of your own applications. You can use patterns to help you organize code in proven ways to solve well-understood problems.

There are many proven design patterns that help you solve problems relevant to the presentation layers. Choosing the correct patterns leads to more maintainable code that separates unrelated tasks and functionality.

Advantages of Design Patterns

Improves code maintainability.

Introduces re-usability of code base.

Reduces chances of modifications in the base core functionality code.

Adheres to TDD (Test Driven Development).

Simultaneous code development and reduced dependency.

Loosely coupled development.

Dynamic code extensible.

Accommodating dynamic business requirements to a certain level.

To know more about Design Patterns, please click here.