I set my system for mono, and played from one speaker.
Didn't care for it. Sounded a bit thin, beyond the cancellation effects of combining channels.
Swapped speakers.
Same. I didn't move a speaker to the center. That would just be too much trouble.
Played from two speakers. Better. I'm not annoyed by a mono source, if that is what it occasionally is.
Returned to stereo mode. Ahhh. Back to normalcy.
That's what I will stay with.
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Sometimes I will reduce the stereo width (my Behringer DEQ2496 can do that) if there is something to which my ear objects.
I did that recently, re-watching It's a Mad, Mad, Mad, Mad World, which overcooks the hard left/right pan, for example, on two people standing next to each other right in the middle of the screen.
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Note: Playing from a single speaker (instead of two) drops the sound level by 6dB for coherent sources (I would have guessed 3dB in the past, but I can be wrong about things like this), could be more for some sounds when the source is stereo and there are phase cancellations in the summation, so that should be accounted for in your critical testing.