It is very difficult to determine all of the crucial factors to starting a business without a well defined business plan. A plan will help you clearly see what your personal goals for your business are, what your start-up costs will be and how long it will take you to earn a profit. You will need to set specific business objectives beyond the desire to make money.
A well defined business plan can increase your belief in your potential success or convince you the business is not really the direction you want to go. Do not underestimate the importance of a plan simply because you are starting a home based business.