Utility patents are the best way to protect most inventions. But to get one, you have to convince a USPTO examiner that your application is worthy.
Utility patents are by far the most common type of patent. In fact, the term “patent” almost always means “utility patent”. Almost all of the famous patents in history – the telephone, light bulb, transistor, airplane, motion picture, are utility patents.
What is a utility patent? Under US law, utility patents are the type of intellectual property (IP) that covers: “a new and useful process (e.g. a method of doing something), machine, manufacture, or composition of matter (e.g. a drug), or a new and useful improvement thereof.”
Note the underlined new. To get a utility patent application allowed (granted), the applicant has to prove to skeptical USPTO examiners that the invention really is new, and not just a trivial (obvious) tweak to older prior art.
Here “useful” means that the invention must have some actual benefit (isn’t clearly impossible or too illegal) and does more than just being decorative.
Utility patents are often the hardest type of IP to get. USPTO examiners usually attempt to use prior art to reject new applications. They expect applicants to rebut their rejections, often several times, before allowing the application. This process is called patent prosecution. If the applicant does not successfully rebut the various rejections, the application goes abandoned.
Legally, a US patent gives the owner the right to sue to collect royalties/damages and/or to attempt to block someone else from practicing the invention in the United States, but not internationally. The exact scope of legal protection is determined by the patent claims.
Patent valuation: Patent valuation is dictated in part by the desires of others to practice the invention, the effectiveness of the patent in thwarting these desires (what the claims cover), and the invention’s potential market size. If a particular patent covers an invention that no one else wants to practice, that patent isn’t going to be worth much!
Assuming maintenance fees are paid at 3-4, 7-8, and 11-12 years after issue, US utility patents typically last for 20 years from initial filing, sometimes more if the USPTO has taken too long to review the application. After that, they expire and become public domain.