Depends on who your professor was. I worked as an engineering lecturer for a few years. I told my students that having a reference text can be invaluable as you move through your career. For certain kinds of engineering, this is absolutely true. Paper reference texts have little long-term value in computer engineering. But civil or mechanical engineering? The principles of material strength do not change. And that’s the kind of engineering I teach. So I really encourage students to get paper reference texts.

To facilitate this, I would always post homeworks that included scans of the full problems. I either wrote the problems from scratch or cut out problems from the textbook. It then told students to still buy the book, but buy a few editions back to get their reference text for a song. I still want my students to have a permanent physical book, but if you design your course right, they won’t need the newest edition.