There's pretty much always something that needs to be done, even if I have some time when I don't have specific "assignments" or what-have-you. So I can always

There's pretty much always something that needs to be done, even if I have some time when I don't have specific "assignments" or what-have-you. So I can always just grab something off of the "backlog" / "todo list" and work on that. And sometimes I do. Other times though, I choose to use some "free" time for learning. I have a number of courses queued up to work through on sites like Udemy, LinkedIn Learning, Egghead.io, etc. And there's always Khan Academy, papers on Arxiv.org, JMLR, JAIR, or old conference proceedings from IJCAI or something interesting to read and study. Not to mention a huge list of interesting Youtube videos to watch.