Return midterm exam paper or not I wonder how common for professors to return scored midterm papers to students when the final is not accumulative? I want to reuse some of the questions next year and also is not willing to spend about 10 minutes class time just for returning the papers (90 students).
In mathematics in the US, as far as I know, I have never known any professor to ever not return midterms. I always do, and everyone else I know does as well.

Seeing their graded midterm gives useful information. It lets students know what they have gotten wrong and what they have gotten right; it also lets them know what answers they thought were "right" but in fact are incomplete or inadequately explained.

I personally believe the downsides are miniscule in comparison to the benefits for the students.