Posted By Debbie Rose I was under the impression it was that also. Nothing is set in stone on this or in the regs

Posted By John Webster Size, as they say, is not important. It really does depend upon how much information you need to display at one time. A good quality 9inch black and white screen (as per old Macintosh SE30s), with correct contrast and brightness can be better than a poorly set up 17 inch colour monitor. The problem is that modern software generates so many toolbars etc that the actual information window is often no bigger than a 9 inch screen anyway. One aspect which seems little discussed, but I find very important, is Refresh Rate. Many monitors default to something like 60Hz. I am not alone in finding this gives me a headache (from the almost imperceptible flicker) which disappears when I reset this to 70 or 72Hz.