Textbooks don’t need a lot of revisions though. Basic math has not really changed that much. One of my favorite textbooks I used as a kid was written ten years before I was born.

When I started Chemistry in college, Professor Zumdahl said to by a copy of the CRC Press Handbook of Chemistry and Physics. Whether it was new or used didn’t really matter - it’s not like Boltzmann’s constant is changing all that often.