I'm all for having a business plan in the verb sense. I'm just not a big believer in the noun form. Writing a formal business plan invites the paralysis of analysis. If you must write a business plan, see Exit Strategy, for the five critical questions your business plan should answer. Because yeah, sometimes you need one. It distracts the entrepreneur from slaying dragons and thinking big thoughts. The result usually is a long-winded missive that's out of date almost the moment the ink dries.