This. I finally finished one sketchbook about 6 years ago- and started working on 2 more(one is a small one that I can stick in my bag and carry with me; the other is a large one that I drag around to conventions and scribble in it when I'm in lulls between selling stuff)...I've currently slowed down on scribbling in my sketchbooks over the last couple of years- even moreso since I've gotten into a lot of digital scribbling. A lot of my sketchbooks are just that- sketching and drawing/inking; I never do full color pieces in a sketchbook.
When I was doing comic work traditionally I never cared for erasing on the bristol; I'd do all my erasing in thumbnails, then blow them up(via copier) and do the final pencils(via lightbox) in non photo blue pencil, then ink right over it. The blue line would not show up during printing, this became a "way of life/process" for me.
My biggest thing is I try not to waste a lot of energy when drawing/inking/making comic pages. It might be because I'm older and I dont have a ton of energy like I used to, but when I do start working on stuff I'm always trying to find a way to do a thing quicker/faster with the least amount of energy...I do it even more now days with the all the arm issues I've been having on and off for the past couple years.
@fleohr just now starting to get used to doing art on my iPad. Only obstacle I have right now is that I need to "convert" a couple of PS brushes to CSP brushes so that I can exclusively work in Clip Studio on my iPad.