At least one extra screen is essential for me. Many years ago I posted about Organizing Windows and Multiple Monitors.
When I migrated to using a Mac most of the time, as well as using an iPad for many things, I was happy to know there was a way to use the iPad as a secondary monitor. That to me was great because whenever I wasn’t at my normal working place (maybe traveling to clients or conferences) I always have both my Mac and my iPad with me, so I could still work in a dual-screen set up (not huge screens like I prefer, but still…).
At the time I wrote up about that: Setting an iPad as an extra monitor. That approach, however, wasn’t flawless. The app I was using, Air Display, connected the Mac and the iPad through the wi-fi network. In some networks, I just couldn’t get this to work. Also, there was a noticeable lag when moving between screens.
Fortunately, about a year ago I found this app: Duet Display. Life was good again. This app uses the iPad USB cable to connect to the Mac, and it has zero lag.
Now I just need to get me that bigger iPad!