In general, diary is needed by everyone.
Everyone needs a diary to write his/her short-term and long-term plans. A diary is needed by anyone like a kindergarten child, a primary school pupil, a student, a businessman, a civil servant, a farmer and the leader.
There are two groups of people who use a diary differently:
1. Firstly, there are those who need Diary just because they like doing so. That's they have the passion of keeping a diary. 
2. Secondly, there are people who need a diary because they are supposed to have it regarding the kind of work they do or they need to do. These people outnumber those who are just interested in keeping a diary although some of these are just obliged to have and have no passion of keeping a diary.

Now, the following are some kind of people who need diary in their everyday life or work life:
- Storekeeper
- House maid
- Police officer
- Nurse
- Doctor
- Shopkeeper
- Librarian
- Teacher
- Secretary of any Committee
- Chairman of any Committee
- Artist
- Entrepreneur
- Driver
- Journalist
- Radio/TV Presenter
- Writer of the books
- Student
- and many more

So, if you look at the list above, you will find out that almost everyone needs to keep a diary to do their things in a right way. However, keeping a diary is not an easy work. It needs practice. We still need some skills regarding the use of diary as our support to improve our life work improvements.