To those with 2+ monitors on your machine: What's your use case, and how much does it actually boost your productivity?
I'm mainly curious about software developers here, or anyone else whose computer is somewhat central to their life, be it professional or hobbyist.
I only have two monitors—one directly in front of me, and another to the right of it, angled toward me. For web development, I keep my editor on the main screen, and anything auxiliary (be that a dev build, a video, StackOverflow, etc.) on the side screen.
I wouldn't mind a third monitor, and if I had one, I'd definitely use it for log/output, since currently it's a floating window that I shuffle around however necessary. It could be smaller than the other two, and I might even turn it vertical so I could split the screen between output and a terminal, configuring a AutoHotKey script to focus the terminal.
Two screens. One is dedicated to the IDE, the other is everything else: browser, mail and chat clients, docs, maybe another IDE with a REPL to play with stuff.
I find I need a large code window. I know devs that use a 4K monitor the same way, but I don't have one.