It looks like you're new here. If you want to get involved, click one of these buttons!
I just finished all of them a few days ago and I started early October. I've also seen all of LBD and Sexplanations, most of Scishow and about half of Crash Course.... I feel like I'm missing something. Oh! Um, what's the name of the channel that's mostly lists of things (50 facts about states, etc) and is mostly John? I've seen all of that one also.
I've seen all of them. I watched them over the course of about three months, but the bulk of it (about 800 videos) was done in four days.