Do speaker wires have to be the same length for each speaker?

This is almost as entertaining as a closely matched UFC bout.

I prefer same length, but I need to ask the OP: "Why NOT the same length?"

If you're running in-wall, got it.  But if not in-wall, you've got plenty of space in your listening room if you have to drape/coil/hang/etc. (there goes another discussion...) the excess on the longer side.

Hey Christian:  Hi they are not the same length because one speaker is +/- 10 further from the equip. The stereo is in the corner of the room due to fireplace location, sliding doors, etc... Also the wire to that far speaker goes under the house so that adds a few feet as well.

Ah - so custom install, not quite full in-wall, but close.  Yes, no issues with differing lengths.  I've said before I have a tough time discerning differences between cables, but if say you have your audio rack on the outside edge of once of the speakers (which I thought was the case), why not buy an identical set, and just coil/drape/suspend/whatever the cables over to the speakers.  If anything, as said before - it would help with resale, but I figure you won't be reselling the underfloor wire anytime soon.  Sounds like you've got a fun project ahead! 😃

Funny thing I've done a lot of auto/equipment installs for stereo gear. I use to cut and trim all the extra wire. Nothing was the same length.. Butt connectors everywhere then shrink and zip tie everything.

Same here - I started doing my own car audio custom installs in college (were those the days!) - underseat/trunk/dash mounted amps, and wires of way too varying lengths going all over the place.  It's probably the OCD in many of us when I got into the home stereo listening craze (er- wife calls it a disease): a pair a speakers, audio rack in the middle, and EQUAL length cables. 😋

Again, not sure if I could tell the difference if one side was longer than the other, but it wouldn't "sit" right with me if they were differing lengths. 

That's the UFC bout portion of this discussion, @limomangus .

Yes, you can have a pair of speaker cables of different lengths to a stereo set.  Technically, the % difference in electrical parameters of two different lengths of speaker cable is very small.  So there's arguments on both sides on whether it's audible or not.

For me, I wouldn't be able to discern the difference - too busy listening to the music.  However - the difference is still there (audible or not), so why not make them the same length if you easily can?  But also again, for custom installs or other extenuating circumstances which make it hard to keep both lengths the same - cut away!