How important is it to have identical speaker cable length?

My deep seeded neurosis won’t allow me to do that. I would lay in bed staring at the ceiling. But for normal, well adjusted people it’s no issue what so ever. Only issue I can think of would be value when it’s time to sell. All the best.

LOL @ arch2

I would not fret…

But when the capacitance is # pF/meter, and inductance is @ uH.meter then the number of meters can matter.,, and the resistance is also expressed in @/meter (or per foot in freedom units).
It should make a measurable difference, which is better than a physiological difference. IMO.
But I doubt one would hear much of a difference. The room would likely have more of a difference.

To the speaker, no, a small difference is not a big deal.  But holmz is right, the additional pFd and uH could make a difference to your amplifier.  Remember, the output is also the input due to the feedback network.  As long as your cables are low in inductance and not too high in capacitance, you should be okay.   On the other hand, I have had good amplifiers tendency to oscillate when the capacitance in the cable is too high..

This depends on the wire gauge of your zip cord ;-)