It's a relatively small lab in a university and part of my job is keeping the computers running.

I could wipe, but I want to make as little work for my replacement as possible. Well, maybe a few minutes of extra work to get rid of a screensaver.

If it's a desktop workstation with lots of expensive development tools installed or a delicate toolchain (especially one in a lab), why spend the time and effort wiping the thing just to reinstall all of the same stuff over again? It might even be a shared computer. I remember my help desk summer job, I worked at a hot desk that was staffed 24/7 so the same computers were used by first, second, and third shift. There were a lot of things that had to be logged into (mainframes, customer email accounts, etc) and not all of the desktops covered the same customers so it would have been a nightmare to handle all of the images and configurations. Whenever a configuration had to change, they would make a new backup to cover that specific desktop in case it died.