Portrait image in Landscape to edit

Do you ever take a portrait type image and place it in landscape viewing mode, then turn your monitor to view it in as a portrait, which gives a larger format?

I have done this, seeming to have a larger image to work with while editing.
Am I fooling myself or is this a good idea?

Well, not everybody has the rotating monitor to work this way.
So sure, it's a very good idea. That's one of the reasons manufacturers made this kind of monitor.

I'm not sure how you are doing this. Rotating the image within PS or using the options that come with the OS/video driver to turn the whole screen display. If you use the OS/video driver option you will probably want to make and save a suitable workspace with the tool pallets arranged across the top/bottom of the rotated display. This would be especially true for a wide screen monitor, which has plenty of room either side of (a normal landscape) a DSLR's 3:2 image. Without moving the tool pallets then I don't think you will gain as much as you expect from rotating the screen. As my display is non rotateable on it's stang I have never tried this. Back when we all had 3:2 monitors rotating the screen would enable you to nicely fit a word document on screen, with toolbars top and bottom; using the "European" A paper sizes is also an advantage with their 1:1.414 ratio.

Alan