I will be using two external screens. My main question is about aspect ratio. Years ago when switching from a square desktop monitor to a rectangular laptop screen I had some programs that didn’t work well with the new aspect ratio. I’m wondering if these new 16:10 screens will cause problems if a program was written for a 16:9But to possibly answer your initial question on screen sizes...i have an 8 monitor setup as i day trade a lot, but swings are my main thing. strictly my opinion here, but screen size and the number of screens really depends on the amount of information you need and can take in...more isn't always better. Depends on your style and methods of trading. I could do away with the 8 and only use one and do fine, but would miss some of the trades i take as the other monitors i use for running scans