Between my job and family I will not have the time to work through all exercises with the level of attention that each deserves; add to that the fact that I tend to be a slow reader generally (especially in math) and you get a student in the slow lane. While the course will likely move faster than I can keep up with that is absolutely fine and i don't expect the course to slow down for me and I am used to that! For me it is absolutely the explore/exploit tradeoff - I will scan the book and comments knowing that I will not have enough time to engage all questions at the level I would like, so I look for those exercises and/or comment threads that seem to be in the sweet spot for yielding the most learning with a deeper dive.