Do speaker cables need a burn in period?

Absolutely! My QED Signature Spk. wire sounded pretty good from the start but it wasn't till about 150+ hrs. when "it" happened. Glorious sounding cable especially for it's very modest price. 

Yes! 

Yes

The most of the “good” speakercables takes about 200 hours.

This subject always made me grin. A friend who has a degree in electronic engineering laughed at these thoughts. He said speaker cables do not carry enough current to affect their physical nature. Also, what is "burn in" or "break in" anyway? What actually happens? What happens to the cable that actually changes the sound? I've yet to see that explained to the point where it makes any sense. However, if that is what you want to believe, so be it. What if the cable "sounds" worse after break in? A change in sound isn't always to the positive. Have fun!