Have you ever thought about what makes up a library? A library is a collection of useful methods just as a book library is a collection of useful books. So is the case with an application library contains numerous useful methods and elements. The emphasis is on the word useful to stress the importance of not having redundant methods and elements in the library. A redundant piece of code requires documentation. When the company spends resources (essentially money), it will never want to have entities that have less usage. What is the reason for this? The principles of economics—the primary objective of any company is to maximize profit. No matter what!