It's definitely an attention span thing with me. The ones where we're working with the puppets, it can be a slog to make very long videos, because it's not just setting up the camera and standing in front of it...we have our arms up in the air above our heads, and that gets really tiring. Also, I think when I'm doing comedy, if I give myself more time, it just loses some of the fun.
My cooking videos are a little bit longer, but again, I don't really like watching a 20 minute recipe, so I like to just give the information, show a few visuals of the process, and talk about the results.
Hair videos are a bit more rambling, but that's because I'm talking to a group of people who I "know" (as much as you know someone through comments on channels). It's like a hangout session more than anything. I rarely do much editing on my hair videos; they're generally one long take.