Because writing is, or should be, for yourself first of all, everything you write involves at least some purpose that benefits you. Of course, expressing yourself is a fundamental purpose of all writing. Without the satisfaction of expressing your thoughts, feelings, reactions, knowledge, or questions, you might not make the effort to write in the first place.
A closely related purpose is learning: Writing helps you discover what you think or feel, simply by using language to identify and compose your thoughts. Writing not only helps you form ideas, but actually to promote observing and remembering. If you write down what you observe about people, places, or things, you can actually "see" them more dearly. Similarly, if you write down facts, ideas, experiences, or reactions to your readings, you will remember them longer. Writing and rewriting facts, dates, definitions, impressions, or personal experiences will improve your powers of recall on important occasions such as examinations and job interviews.
