Author here :) Fortunately, I mostly don't idly browse the internet on my computer - that habit is attached to my phone, which I just leave in the other room :) But in general, yes, if I need a break, I check off what I'm currently doing, write down "break", and then take a break, and check that off when I'm done. But my experience is that it's probably best to keep your breaks physically separated from your workspace if possible so that when you sit down to work it feels like "work time".