How important is it to have identical speaker cable length?

I say do what you need to do and enjoy the music. 

Anything more than about a 4" difference in length will smear the center image.

If you're ok with that, go for it.

And by '4"' I meant 400 feet.

@jerryg123.  

“Even if engineers have said the values are so minute the human ear can not differentiate the capacitance or inductance.”


Especially if engineers say that. Going by “engineers” quoting variables is the best way to end up with a poor sounding system.

And how about having bi-wired two lenghts, LF 1 meter shorter then HF? 

Perhaps you could think about making your room bigger to facilitate same length cables.