This morning as I rode my bicycle, I thought back to an experience I had with one of my Electrical Engineering professors. A group of us were talking about the rapid advancements of computers and a new interface had just been announced that allowed you to watch television in a window on your computer. I thought it was great as you could work on your computer and watch TV at the same time. My professor remarked, "Why? Just get a TV and put it next to your computer."
He was right as this was back in the days when most computer monitors could only display 640x480 pixels, which is about the size of a regular NTSC television picture. While I had a more advanced computer that could display 1024x768, it could only do so with 16 colors per pixel. To get more colors, I would have to reduce the screen resolution. Furthermore the price of card for the computer came in at around $500 while a new television only cost around $300.
Fast forward a few years and I remember attending one of the last COMDEX shows in Las Vegas. I stopped by one of the Linux booths and they had 3 monitors built into a single unit. Of course it required that you have 3 VGA outputs on your computer to run all of the monitors but I thought it was spectacular and wanted one badly. Unfortunately it was cheaper just to get 3 monitors and I could not justify the extra cost. Consequently I never added the necessary hardware to my computer and continued running with a single monitor. By this time, resolution had increased to 1280x800.
At around this time, my primary computer became a laptop as I spent a lot of time traveling. The standard laptop resolutions seemed to be fine and I didn't really worry about needing more screen real estate as there is only so much space on an airplane. During this time you can guess that I traveled a lot.
Eventually I moved into more of a development role and worked on a project that needed a second monitor. Rather than fall back to the default monitor size of the day, I splurged and picked up two 1920x1080 monitors and put them side-by-side on my desk. I really had to clean a lot off so they would both fit. I also had to get a new computer with dual monitor outputs to drive both displays. I enjoyed having all the extra space.
My dual monitors lasted for quite a few years. They worked well and I discovered that I could keep them both filled with information to help me in my work. Of course technology continued to progress and so when the price of 4K (3840x2160 pixels) monitors dropped to where everyone could afford them, I jumped at the chance to get one. They are the equivalent of having four 1920x1080 monitors grouped together. It is the monitor I am using right now and guess what? I have the entire screen filled with 10 different windows. I also have a second computer with the laptop screen and a third 1920x1080 monitor. Both of those screens are also filled.
I guess the whole point of this post is that the answer to the question posed in the title is, "Yes," for both. You can always use more monitors and more screen real estate. At least I can.