When running live sound in mono should I pan everything to 1 channel or use splitter and pan everything to middle coming out both channels

Frank, What exactly are you trying to accomplish? Are you attempting to do a single mix with only 1 output/speaker? Depending on your personal preferences, if you are using multiple outputs, then you should be running everything in stereo. It is more difficult, but when mastered, it will give you a better sound than just mono. For example; If you are amping your drums, they should always be panned in the middle. That is, unless you are going for individual snare separation. If your lead guitar stands to the left of the main vocalist, then the guitar should be panned slight left. Rhythm guitar should be in the middle. ETC. Remember, in the end, it all comes down to the sound you are trying to attain. So as the sound mixer, the ball is in your court. ^^ Good luck, and hope this helps.