THE first time I adopted dual-head setup was about 20 years ago (slightly more). I realised that my laptop had support for it, so I'd always plug it into a bigger external monitor (back when they were all CRTs). I never ran any more than 2 screen on one single device because those sorts of setups require expensive hardware like graphics cards which cost more than a whole new screen. About a decade ago I started working with two computers in parallel, seeing it could enhance productivity and be made to work from one pair of peripherals owing to Synergy. There's one primary device (with better hardware) and one almost disposable hardware (enough to just display things or remotely connect to stuff). One such device cost me only 40 pounds (about $50). It was not energy-efficient though (power bills probably cost more than the device itself).

"So my 6-screen setup costs well under $1000 to put together, including the 3 laptops."Low-cost laptops (used or low-spec) can still be used as secondary devices and get connected with ports (VGA, DVI, HDMI) to external screens, which don't cost that much either (especially second-hand/refurbished ones). So my 6-screen setup costs well under $1000 to put together, including the 3 laptops. A lot more can get done and more things be noticed in real time provided one's field of vision is partly occupied. The military (e.g. submarines) and aviation companies reached similar conclusions. It's usually better to have more in sight than to minimise scope, provided what's in sight does not generate too much unwanted and unnecessary distraction (those things can be optimised for the user over time). In the video above I answer a common question and explain how I work. In terms of ergonomics, I've generally found that lifting the legs (about 90 degrees upright) helps a lot, especially for those working long hours. Circulation is very important. ⬆