I am a materials science graduate student so I have not taken the full set of courses that a physics or applied physics graduate student would. It is very important to me to have a strong understanding of all applicable areas of physics - classical E&M, quantum mechanics, statistical physics, solid state physics primarily. If I find a textbook that I like, I really enjoy reading it, and I would often rather do that than read current literature. I have a belief that with a good enough understanding of these areas, I will be able to readily grasp most arguments made in the experimental literature, and more quickly pick up much of the theory for specific subfields (like ferroelectricity, which I am currently working on). So in that sense it is certainly beneficial for me to read background texts. However, my current research doesn't have any immediate need for much of this theory (although I could argue that it is impossible for me to see how a certain formalism might be applicable if I haven't mastered it). There is effectively no limit to how much time I could spend reading current literature and trying to enhance my knowledge of the state of my field. When I am reading background physics which I enjoy, at what point should I guilt myself into reading more of the literature instead? Of course one doesn't need a full mastery of everything that has come before in order to make incremental progress in a field. Is it the job of the graduate student to focus on the forefront of their field and only bulk up on background when the research demands it? Or is it common practice to continually devote a chunk of time to this in the hope of being a more fully realized scientist a few years down the road?