I definitely find dual monitors or more for splitting code, documentation, or other relevant project information to be similar to having multiple papers lying across my desk. I don’t want to stack the pages on top of one another but instead I prefer to lie them all on one large desk. Usually I’m only working on one page but need other references. If another paper truly is important than I can use Spectacle to quickly reorganize.

Having email, slack, discord, or HN open is an absolute no go. Nothing more distracting than focusing on a project and seeing new emails or messages stream in. I try to limit those to a separate laptop or tablet at all times.

I’m just like you. In the afternoons, I switch from my monitor to just my laptop. I sometimes prefer a smaller screen so I experience less eyestrain

It's not so much about number of monitors but screen estate.