[Svartalfiar]

They would change a few sentences here and there, then reorder the chapters to render older editions barely usable. Buy a new book, $150, but it used, $90, sell it back, $25.

Actually, the main thing they did to make old editions unusable was to completely redo all the check-on-learning / homework questions. It's easy enough to use a textbook with mixed-up chapters, but if the homework doesn't line up with the assignment, that's the difficult part.

[brownsfan]

” … but if the homework doesn’t line up with the assignment, that’s the difficult part.”

I thought of that after I posted. College was a long time ago for me. :)