I am currently enrolled in the 9-week MGMAT program.

With the release of new test prep editions from GMAC, and of course every new GMAT exam; do the 9-week course content and books lose relevancy or accuracy as GMAC continually updates its products? If so, what's the "half-life" of this knowledge once complete?

In other words, will you soon publish a new set of 8 guides, will I [should I] have to go out and get the new editions of these guides, and is my prep work still insured from obsolescence for the next 6 months or so?

Thank you!

The test doesn't change anywhere near that quickly. :)

The OG 11th edition and supplemental books were first published a few years ago, and they haven't changed since. The previous edition, the 10th edition, has 75% overlap with the questions in the 11th edition, and the 10th edition was also "live" for several years. Although the database of questions for the official test does change every month to ensure that repeat test-takers don't see the same questions the next time they take it, the types of questions themselves evolve very slowly. (I could write 10 "different" questions just by changing a few numbers or words in each problem.)

Remember that this is a standardized test - it stays substantially the same over any several-year-period of time. The people who apply to b-school next fall may have taken their GMATs two days, two months, or two years (or longer!) apart, but the schools still have to be able to compare between these students.

So, short answer: you're fine. Now, if you decide to put your books aside and pick them up again in 5 or 6 years, I can't guarantee that they'll still be completely relevant...