If you need to get going quickly to ride the wave of a fad before it fizzles, then fast, bare_bones planning may be all you've got time to execute. This works best when you've already got the infrastructure in place, perhaps from previous projects or an established business, and you can simply shift energy and resources to the new idea.
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.