Planning is very important in life. Everybody should do planning at individual or family level. As an individual, you should plan for the day well in advance in order to accomplish what is to be done in that day. At family level, a family plan helps to focus on supporting the entire family in its growth and development. Planning is also done at business and organizational level.
There are many reasons for utilizing such a document. Is the final document going to be about implementing a decision already having been reached or is it about analysis and recommendations for a newly proposed activity. As noted above, a finished document may be for internal or external purposes. Externally they are often used to solicit funding for a start_up or joint venture. Whatever the purpose, do not confuse effort with say, a marketing or a production plan.