There are a few circumstances when you can use someone else's copyrighted material without getting their permission. These are called "fair use" or "exceptions and limitations." Fair use is decided on a case-by-case basis and depends on factors such as the purpose of the use, the nature of the copyrighted work, and the amount used. Some common examples of fair use include using copyrighted material for the purpose of criticism, commentary, news reporting, teaching, scholarship, or research. It is important to note that fair use is not a defense to copyright infringement. If you are accused of infringing someone's copyright, you will need to prove that your use falls under one of the exceptions or limitations.