For example, the inventor needs to consider whether the technology will be obsolete by the time the patent would be issued. The alternative is to maintain the invention as a trade secret. A famous example of this is the formula for Coca-Cola. Another circumstance of opting for a trade secret over a patent is when a complete description of the invention would allow competitors to use the invention without being detected. A manufacturing process is a good example because it's hard to determine whether a competitor improperly used a patented process to produce its products.
Trade secrets have their down side, too, though.
A company has to be careful with those items that it chooses not to patent. A copyright protects an author's original works against copying. Unlike patents, copyrights are very easy to obtain. In fact, works are automatically copyrighted from the time they are created in fixed form. This registration establishes a public record of the copyright claim and is a prerequisite for suing another party for copyright infringement.