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

They must be the same length, or you will hear an echo.

Have different length cables and there’s no echo or any other issues

Nice if viable but not always possible.

ok another question, can I splice 12 ga. to say 14 ga. wire? I don't have a high end system, just don't want to spend $$ on a roll of wire if I can avoid it. Old Pioneer sx980 w/ klipsh forte ii, standard A/T turntable + cambridge CD player.

Yes, you can do it. Won't hurt a thing. Will save you some money. Then maybe some day later on down the road you get something better. Until then, relax and enjoy.

Maybe it makes a difference if one line is 250' and the other is 4'. I like to have them at the same length for the superficial symmetry thing.