I agree with
logro that questions that appear in the OG are retired. Certain questions from the same RC passage may not appear from one edition to another, and it is also true that some identical CR passages include a different question and accompanying answer choices. Does this mean that all the questions from, say, the RC passage were retired at the same time, but that only some of them were made public, or does it mean that those hidden questions may still have been active while the others were retired? Only GMAC™ knows for certain, but I would wager that passages are retired altogether, with questions or variants leaked little by little. In this manner, the integrity of the test is not compromised.
To touch on the question you asked about an annual reset of sorts, again, only GMAC™ knows the answer, but I imagine that there is a vast pool of potential questions that get cycled in and out based on the exam algorithm, and that this pool of questions consists of some new, some relatively recent, and some never-before-released-but-not-so-recent questions. With such a large base of questions, there would be no need to test thousands of new questions each year, and even a crack team of investigative reporters—as I will call people who take the exam with the intent to get the inside scoop on the questions and tell others about their findings—would have trouble pinning down just what the different questions were.
Concerning content, though, there will be some overlap between questions from time to time, but that is exactly how a standardized test should operate. In fact, I have even spotted,
on a different exam, a question that was identical to one on an official practice test, just with the numbers changed. It was the same question number and everything. Granted, that was a paper-based test, but I suspect that the GMAT™ would be no different. Study that official material!
Thank you for your question. Good luck with your studies.
- Andrew