Design patterns are the reusable solutions that solve common problems of soware

development. These problems include repetitive code, redundant functions and logic

etc. These help to save considerable effort and time required for the developers while

developing soware. Design patterns are commonly used in object-oriented soware

products by incorporating best practices and promoting reusability for developing

robust code. 

https://refactoring.guru/design-patterns

Design Patterns have become an object of some controversy in the programming world in recent times, largely due to their perceived ‘over-use’ leading to code that can be harder to understand and manage.

It’s important to understand that Design Patterns were never meant to be hacked together shortcuts to be applied in a haphazard, ‘one-size-fits-all’ manner to your code. There is ultimately no substitute for genuine problem solving ability in software engineering.

The fact remains, however, that Design Patterns can be incredibly useful if used in the right situations and for the right reasons. When used strategically, they can make a programmer significantly more efficient by allowing them to avoid reinventing the proverbial wheel, instead using methods refined by others already. They also provide a useful common language to conceptualize repeated problems and solutions when discussing with others or managing code in larger teams.

That being said, an important caveat is to ensure that the how and the why behind each pattern is also understood by the developer.

Without further ado (in general order of importance, from most to least):