> So why are we spending money to display multiple things simultaneously?<p>Full-stack and front end developers can really improve productivity drastically and reduce ALT-TAB Keystrokes and back-and-forth scrolling when developing and testing web-pages, responsive sites as well as web applications that they use an IDE for.<p>At work, I have 2 monitors (21-inch each). On 1 monitor, I write my code in an IDE, usually Visual Studio or sometimes in Notepad++. On the other Monitor I have the website that I am building, open. As and when I make changes, do a build, I simply have to refresh the screen on the other monitor instead of pressing ALT-TAB over and over again and selecting the other window, if I had just 1 monitor.<p>The 2nd use case, also common for full-stack or web developers, is when debugging front end stuff like Javascript, CSS, HTML. I have the webpage open in 1 monitor, and the chrome debugger in the other one, so I have a full screen on each side to do the debugging. This exercise becomes especially tedious with a single monitor, wherein, when you go F12, the chrome debugger will occupy a good portion of your screen, no matter how you've docked it (to the left, or right or the bottom).<p>On a single monitor, this means endless clicking, scrolling back and forth on the page you are trying to debug, next think you know, your fingers and wrists are sore and you haven't gotten too far in your work and your coworkers tell you that you have RSI.<p>I wonder if OP is a command-line / backend developer, in which case, you may be able to get away with a single monitor and not feel the pain :)