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.
I have 4. My main and second are 46" each, the 3rd. is a 27" in normal/landscape, and the 4th is a 27" in portrait. The main is in front of me, the 2nd. is to the right and angled toward me, the 3rd. faces me at 90 degrees from the main, and the 4th. Is mounted above the 3rd. I used them originally for streaming and all of the windows I had open to monitor everything at the time as well as the game I was playing. Now I find them useful for working on projects, watching videos or movies while I play a game, and working on multiple spreadsheets at the same time. The one in portrait is especially helpful when I'm looking at a season's worth of a scheduling spreadsheet.