Conducting a thorough patent search is difficult, particularly for the novice. Patent searching is a learned skill. A novice in the United States could contact the nearest Patent and Trademark Depository Library (PTDL) and seek out search experts to help in setting up a search strategy.

Although, the length of utility and plant patent protection (patent term) was previously seventeen years from the date of patent grant, utility and plant patents filed after June 8, 1995 now have a patent term of up to twenty years from the date of filing of the earliest related patent application. Utility and plant patents which were applied for prior to June 8, 1995, and which were or will be in force after June 8, 1995, now have a patent term of seventeen years from the date of patent grant or twenty years from the date of filing of the earliest related patent application, whichever is longer. Utility patents are subject to the payment of periodic maintenance fees to keep the patent in force. Patent terms can be extended under some specific circumstances. See the U.S. Code Title 35 - Patents for a full description of patent laws.

Laws of nature: Galileo would not be able to patent his findings from his experiments at the Leaning Tower of Pisa. Physical phenomena: Patent law classifies physical phenomena as products of nature. Thus, if your invention occurs in nature, it is a physical phenomenon and cannot be patented. Abstract ideas: Abstract ideas are concepts like pure mathematics and algorithms. You cannot patent a formula. However, you can patent an application of that formula. Thus, while you cannot patent a mathematical formula that produces nonrepeating patterns, you can patent paper products that use that formula to prevent rolls of paper from sticking together. Literary, dramatic, musical, and artistic works: These can be Copyright protected. Inventions, which are considered not useful or possible: For example, the USPTO will not issue a patent on a perpetual motion machines; or offensive to public morality.

In the U.S., the inventor has a "first to invent" claim which is different from other patenting organizations throughout the world who generally utilize "first to file." Debate over this issue, and which model best influences economic development is ongoing. Some are concerned that a change in patent rights may harm the small startup and benefit the incumbents with deeper pockets. You can read more about this topic.

Proper organization of a patent porfolio is essential to be prepared to properly navigate the IP landscape. One key issue is related to inventorship. Consider the Pfizer patent, patent # 5,760,06^, which is commonly known as the COX-2 inhibitor. Pfizer is currently in a $1B lawsuit because Searle, the original owner of the patent, failed to include a key inventor on the patent. Pfizer inherited this mess when they acquired Pharmacia, who had previously acquired Monsanto, who had previously acquired Searle. Ignorance is not a defensible excuse in patent litigation.