I've found that, for me anyway, one centered large monitor with enough real estate for your daily tasks is better than N smaller monitors. This is even if "total number of pixels" is larger on the N-monitor setup.

It's one less decision to make 1000 times a day (which monitor should this thing be on?), and reduces neck strain resulting from switching your focus between monitors.

But, it can be nice to have one for output; plots or something.

I assume folks who work in a corporate environment would want one for slack, outlook, or whatever.

With a keypress, I can switch between fullscreen workspaces. Or place two windows side-by-side when needed. My desk is free of clutter, and I never have to deal with configuring multiple displays.

I believe multiple monitors are less elegant and less effective (though a giant workstation full of monitors is perhaps impressive to family and friends).

A similar topic: I also don't understand why some fellow programmers need syntax highlighting. Some programmers have never even tried programming without it! And to them it might feel weird to go without at first, but I think it quickly becomes clear that syntax coloring is noisy and superfluous (and you might end up wasting time picking colors, etc.). Imagine if we did that for natural language (verbs are green, nouns are red, etc.), or math notation (numbers are blue, variables are pink, operators are orange, etc.). The silliness becomes clear quickly.

I used to have three 1080p screens. Now I just have one 4K screen, and I still have more screen space :)

I personally like to use Divvy to chop my screen into sections but mostly I do 2/3 for my IDE (affords me 3 less-than-full-width columns for source) and 1/3 for the browser. I have wanted to have an iPad for displaying docs but haven’t gone there yet.

Both the portrait displays get a good amount of use. The central one is most important of course but the one to the side is useful too as I don't have to turn my head much to look at it. Its usual use is documentation or similar but using it for actual work is no hardship.

The landscape display is mainly there because I work in video games, so I kind of need one. I usually use only about half of it at most, though, to avoid having to turn my head too much. If I was in some other line of work I'd probably have a 3rd portrait display instead.

(I did use the large monitor + laptop below arrangement for a while, and that was good too, but one day I knocked my drink over and it destroyed my laptop. So that prompted a rethink.)