Why cite?

By using the work of others (especially experts), your solution will be better than what you would be able to achieve all by yourself. Together you can do more than alone. You can also convince others of the truth of your statements more easily if, for example, you can substantiate it with data that has been researched by others, or the correctness of a particular choice if you can support it with ideas from experts in that area.

Just look at the following examples. Which do you find most convincing?

Statement Statement with substantiation Statement with substantiation and source
We will develop the application for the Windows operating system. We will develop the application for the Windows operating system, since that is currently being used by most people.

We will develop the application for the Windows operating system, since that is currently being used by most people (W3Counter, 2018).

W3Counter (October 2018). Browser & Platform Market Share, October 2018. Retrieved from https://www.w3counter.com/globalstats.php?year=2018&month=10 (2018, Nov, 26).

Besides the persuasive power, there are other reasons to refer to sources. If you indicate your sources, others can also read that if they want to know more about that subject. And you show that you are aware of what others have done on this topic. In addition, by explicitly stating which parts of the text come from others, you ensure that you cannot be accused of plagiarism.