The class before you have an exam, what is the one thing that most professors do? They give you a practice exam. They show you exactly what kind of problems will be on the exam and what you should be studying. During class, they will even go over what the exam will look like and what questions you should be focusing on.
Studying from someones else’s past exam may be considered cheating, but I think it’s more like studying wisely. If the teacher is already giving you the questions that are going to be included, then what’s the difference between using an already used exam?
Chances are, the professor probably changes the test questions, and they wouldn’t even end up being the same. If you study off of the exam that was already given, it will only help you, not harm you. But “past” is a relative term. Past for me, means months and semesters ago. I do not agree with studying from a test that was given the class period before and then using that to steal answers from. There is a difference between studying and stealing.
If you are not sure about if the use of a past exam is considered cheating, then why not just ask your professor. I’m sure that they would appreciate you asking and finding out before you actually use the test for studying purposes.
Academic dishonesty is a big problem today, but this is just using resources. Professors sometimes even take back the tests after the grade has been seen. If the professor doesn’t keep the test after the grade has been seen, then they are basically just telling you to help someone else in semesters to come. Professors should have an idea that students will use other students’ past exams. They should then just make new copies.
You are not guilty of anything until you take the test. If you are sitting there with papers on your desk doing the old “write answers on your arm or put papers on the floor method,” that is blatantly cheating. Studying a past exam is no different than using the practice guide the teacher has already given out. The chance of remembering all the things you looked at on the study guide is very slim.
There is no reason to believe that you even have the exact same test as the one that you will be taking. If there are students that took the class before and they remember certain aspects, then that is just a study strategy.