From a quick read on Slate offering career and productivity advice from Dave Giboa:

[At] the end of each week I try to look at my calendar and review all the meetings that I had that week and rate them zero, one, or two. Zero means it was a really bad use of time and, if I had to do it again, I wouldn’t have attended that meeting at all. Two is a great use of time—I wanna spend more of my time in those types of meetings. And one is somewhere in-between. And then I’ll connect with my assistant and make sure she understands which of those meetings I want more of and which ones could be filtered out so that hopefully over time my schedule becomes more and more productive.

I wonder what would happen if we asked students to do a version of this exercise each week.