Almost all of the . students are either financed by some form of fellowship or assistantship. Of course, it is better to have a fellowship in the first year so that you don’t devote any time or energy for teaching or grading purposes. But being a TA is not a bad thing. One of the authors of this paper believes that teaching and even grading (unless you happen to grade 400 homeworks every weekend) during the first year helps you to relax. In addition to that, it is very likely that after finishing your . you will need to teach.