I would only use it if I see a problem with the monitor display. So far, I haven't had to use it on my monitor. I worked in a video arcade years ago. We had some older games that we had to deguass the screen.
Degauss is only really supposed to be used if something like a small magnet has unaligned the electron guns, what a degauss will do is re-align them if they are not too far off, it also helps if you are seeing slight distortion due to badly shielded speakers being next to the monitor. (magnets =P)
This is what it says for my monitor from the sony website
This is the sound of the auto-degauss cycle, not a malfunction. When the power is turned on, the monitor is automatically degaussed for 5 seconds. The Auto-degauss function demagnetizes the metal frame of the CRT to obtain a neutral field for uniform color reproduction.
NOTE: If a second degauss cycle is needed, allow a minimum interval of 20 minutes for the best result. A humming noise may be heard, but this is not a malfunction
Yes most monitors degauss at startup, but that is usually before the electron guns have began firing, so i'm not sure since monitor hardware is not my field, but a degauss while the guns are firing might be a little more stressful.
Ep, glad to see you come back and tidy up...did want to ask a one day favor, I want to enhance my resume , was hoping you could make me administrator for a day, if so, take me right off since I won't be here to do anything, and don't know the slightest about the board, but it would be nice putting "served administrator osnn", if can do, THANKS