Another consideration. Should the business plan be a document that is focused on selling an idea for a product or service? For many years I worked in a company that did not want anything in a business plan that could be construed as showing a bias towards or against a project. The mantra was to only present facts in the business plan. The Operations Research Department was there to review the analysis as being unbiased. To handle the "what if" scenarios or sensitivity analysis we prepared a supplemental analysis documents which were mostly financial oriented. Personally, I like a factual approach and use the presentation of the final document to point out the conservative aspects of the content.
To me a small business is one of the best things you can have if you enjoy operating a business; however, it does require a lot more than just enjoying ownership and running a business. Especially if you are starting a small business and even if you have had a business for many years, you should know what you want for your future. Never guess about your business. You see, without a plan, you are just guessing. We business people work hard and we always continue to hope for the best but when we guess, we're taking a lot of risks. You've probably heard the old saying from an unknown author that says, "If you fail to plan, then plan to fail."