When do you really need a business plan?

On a regular basis, I am approached by technical entrepreneurs who assert that business plans are a waste of time. They cite sources such as a recent BusinessWeek story, "Real Entrepreneurs Don't Write Business Plans" (http://www.businessweek.com/articles/2013-04-25/real-entrepreneurs-dont-write-business-plans) and "Investors Pay Business Plans Little Heed, Study Finds" (http://www.nytimes.com/2009/05/14/business/smallbusiness/14hunt.html?_r=0). From my perspective as a professional investor and long-time advisor to entrepreneurs, much of this urban legend advice is just plain wrong.

Of course there are scenarios where a written business plan is not critical, but I haven't seen one yet where a well-written 15-page document or at least a 10-slide pitch is negative. Let's look at some common scenarios and put this into perspective for technical entrepreneurs:

• You don't need or want investors or a loan: With bootstrapping, no business plan is expected...