I have one Sim with five degrees and working on his sixth, just because I felt like having one sim get them all. He's also completed the university sports team career and is working on e-sports. He only needs 8 classes to finish a new degree, instead of the 12 needed for the first degree.
As for using his degrees, I plan to have him eventually max all branches of all careers. Of course, most of them will have to wait until he finishes with university to avoid scheduling conflicts. This is a long-term project and not one I'm in a hurry to finish.
