I mentioned the financial aspect of a plan earlier, so let me add this. Another fact about financials to consider: not all business activities are about making money. Point being, in most enterprises financial considerations are centric to the document. But there are some other considerations. For example, a few years ago I wrote a plan for a new subsidiary that was focused on developing an inventory of patents. The potential financial returns were years into the future. Those patents may or may not ever have commercial value. Another example is a non_profit enterprise that has need for a complete roadmap for growing their profile in a market, of which a marketing plan would be the centerpiece.
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.