Did you ever stop and think what a unique position you're in as a business owner? I don't know of any other way you can have as much control over your success than owning a business. When you work for someone else, you are totally at their mercy as to what your future may be like. It doesn't matter whether it is a private business you work for or a large corporation. Your future is in their hands. The only thing that might qualify other than owning a business would be to inherit or win a lot of money that would give you everything you want in life.
A business plan is essential for all businesses regardless of size, and once one has been written it is also important to maintain and update said plan. That being said, it is important to realize that whilst writing a detailed plan is useful and a good foundation for any successful business, it will not necessarily make the business a success or guard you from all disasters. If you keep up to date with business plan it will prove a really useful tool throughout the lifespan of your business. However, if you grossly over exaggerate profit margins or your budget then your business plan could also lead to failure. Stick to the figures and be realistic and your plan should hold you in good stead in the turbulent business market.