The best piece of advice I give inventors, both independent inventors and business managers, is to do at least a cursory business plan before seeking a patent. Not only are patents expensive, but they teach your competitors a lot about your strategies, technologies, and plans for the future. There really needs to be a good business case for disclosing your trade secrets before you do so.
The business case should be used by the patent attorney to determine how the patent is written and how it is prosecuted. The company’s or individual’s business strategy is used to determine the breadth of disclosure, the focus of the claims, and the breadth of the claims. Many decisions during prosecution, including whether to file one or more provisional applications, how to address an examiner’s rejection, whether or not to use various PCT filing strategies, and other subtle things should also be driven by the business plan.
But one important milestone to meet before even beginning the patent process is to determine if the patent will have economic value in a business sense. Can the product be manufactured and sold for a reasonable price that people are willing to pay? If the patent were to be enforced against a competitor, would it give the patent holder enough economic leverage to justify paying for the patent? Is the advertising value of a patented product worth the money? These are just some of the ways to justify a patent from a business perspective.
An article on Entrepreneur.com addresses this issue quite well for independent inventors.