Scenario:
An instructor has found an article in a professional journal that is particularly useful for a class she teaches every semester. She would like to include the article as reading this semester, and then again next time she teaches the course. Is this a fair use?

Response:
The repeated use of a copyrighted work, from term-to-term, requires particular scrutiny in a fair use evaluation. Such a use explicitly relates to "market effect", the fourth factor in the evaluation. This factor requires one to consider the impact of using a copyrighted work on any market for the original article, including the permissions market. Repeated use, as well as class size, may impact this consideration. Smaller class sizes may mitigate the impact on permissions markets to some extent, and using the article only once, not in future semesters, may further limit the overall market effect of a decision to forego permissions. While not an automatic disqualification, repeated use of a copyrighted work weighs against fair use. For any repeated use to be judged as a fair use, it must be outweighed, in the balance, by the remaining three factors of the evaluation (purpose, nature, and amount).