So you say that second monitor caused neck and shoulder strain and then you say that you use laptop for coding? I notice some mutually exclusive points here.

I worked about a year on a laptop and also used laptop at home a little. It was a horrifying experience, neck and back strain was really big because of terrible posture behind a laptop - low placed screen, too close screen to keyboard and yourself, narrow and unergonomic keyboard, small screen estate.

For me the constant side-to-side, combined with mouse usage was the problem. Trying to re-orient my field of vision (I wear glasses with a strong prescription as well). Looking down or straight ahead has never caused me problems.

I should also point out that on the train, I have a table where I sit (not in my lap, that sucks). I also try to use a stand-up desk more for all-day laptop usage.

I've done the same thing. I used to program with three monitors, but over time I got neck strain from having my body oriented in one direction, but having my head oriented in another. For whatever reason, our necks and heads are more used to looking down than looking to one side for long periods of time.

I'm now down to one monitor and I like it that way. Not that it's saved me in hardware costs much; instead of number and size of monitors, I'm now focused on buying laptops that have a high pixel density. The higher the better. Sadly, there hasn't been a lot of movement on that front in most laptops (I'm looking at you, Lenovo). I'll probably stick with a MBP until other companies catch up.

PS: Before somebody berates me about ergonomics, I use an external keyboard and mouse and I have a small stand that raises the screen to eye height. That's more of a personal preference, though. For about two years, I did all of my programming with a 17" macbook pro sitting on my lap in an ikea chair in a graduate student lounge without any ill effects. But then again, I lift. ;)

> I got neck strain from having my body oriented in one direction, but having my head oriented in another.

I found this went away for me if I balanced it out, such that I was looking right as often as I looked left.

For a three monitor layout, my "primary" monitor should be front and center, and the secondary monitors should be on either side. For two, the divide should be front and center. Beyond three, I grow vertically rather than horizontally. With this, I have no problem.

> using a laptop on the train to code no longer feels limiting

That strikes me as an admission that there IS a productivity gain by having more than one monitor though, physiological issues aside.

Maybe a _perceived_ productivity gain, but yes, having more real estate is nicer. And when it's gone, you notice it. Using a single smaller screen is just different behaviour. More cycling apps, window management, and hotkey usage.

Yes, having to constantly move your head doesn't sound good. Did you try moving the monitors further back, so that you could have both in your visual field?