How far apart do you position your speakers ?

The 83% rule doesn't seem workable in my room. Is there any theory behind it? It seems a rather arbitrary number.

I have no symmetry in my room, so I try to keep both speakers and my listening position at least 4 feet from any boundaries, since I can't even up any early reflections by symmetrical placement.

I sit about 10-15 cm further from my speakers than they are apart (about 2.56 m). I find I prefer my Vandie Quatros to be at least 8 feet apart for soundstage width. I like to be close enough for an immersive soundstage, but not so close that it becomes "heady".

My room is too irregular in shape for any geometric speaker placement method to work, though the irregularity may also work to break up modes.

Thanks, Hornguys, for the explanation. I guess my speakers are harmonically convergent at my current 95% position.