In many cases business plans are very important but so much of the time it's a plan to try to convince someone else that you know what you are doing with your business like banks, investors, partners, etc. Now it's true that a well written business plan can also be a major benefit to your success as well if done right. It can guide you and keep you on track and can be the vehicle to get you were you want to be especially with so many outside forces now days that bombard you. A plan can be extremely important to your success especially when you look at the statistics that says 51% of small businesses fail sometime during their first 5 years.
As a matter of fact, did you know that the Small Business Administration says that 50% of small business owners will fail sometime during their first 5 years? There are lots of reasons but one big one is that owners don't have a plan. Another is they have picked a product or service that doesn't have a big enough market to sustain their business and sometime during their future they will run out of customers.