Salary Survey Extra is a series of periodic dispatches that give added insight into the findings of our most recent Salary Survey. These posts contain previously unpublished Salary Survey data.

Someday, dear reader, when you are a crotchety senior citizen, you will bellyache to your grandchildren, or to the guy in the rocker next to yours, about how computers used to have one monitor. "Multi-monitor? What's that? In my day, we got plenty of stuff done using just one dadgum computer monitor."

Yet despite the rancor of old-timers and purists, "multi-monitor," which Wikipedia notes is also called "multi-display" or "multi-head," has become nearly as omnipresent and unremarkable in the modern IT workplace as swivel chairs and water coolers. How-To Geek even has an online primer with detailed instructions for using multiple computer monitors to be more productive.

Most people who work with a multi-monitor setup for any length of time are reluctant to give it up ever afterward. And while it may seem like a scheme cooked up by unscrupulous computer monitor salesmen to move more product, actual studies have shown that using a multi-monitor setup can increase productivity by as much as 70 percent.

For most working professionals, "multi-monitor" probably means two screens, but three- and four-screen setups are commonly available. And really why stop there? Probably because the productivity gain eventually maxes out, no matter how many docs, websites, or spreadsheets you want to have available simultaneously. After all, you still only have one head.

Still, we couldn't resist referring the matter to our latest panel of experts, the certified Big Data professionals who assembled to respond to our most recent Salary Survey PLUS. What do they think is the optimal number of computer monitors? Here's what we learned:

How many monitors does your workstation need to have in order for you to most effectively do your job?

2 — 51 percent of respondents

1 — 28 percent

3 — 12 percent

4 — 3 percent

More than 4 — 1 percent

That accounts for 95 percent of survey respondents. The rest were somewhat evenly divided between the snark-infused answer options "Since when do they make laptops that have more than one monitor?" and "Anyone who uses more than one monitor is a tech-dependent loser."

What seems clear, however, is that multi-monitor is more than a passing fancy among tech snobs. More than half of the certified professionals who took the survey — people who use computer workstations probably almost every day — believe they are most effective when using a workstation with two computer monitors.

And while the seeming excess of having four, or more than four computer monitors doesn't seem to have widely caught on, it's interesting to note that 12 percent of respondents think the optimal number is three. Can we really be that many years away from a time when even two computer monitors simply won't cut the multi-monitor mustard?