Do speaker cables need a burn in period?

At the very least a few hours of not being moved. 
Never heard anyone report cables sounding worse after a few hundred hours.

At least a week after cryo. When comparing cables at least two days.

Yeah, again. Let's add to it - silver or copper or alloy ? I prefer copper for interconnects and silver alloy for speaker cables with my particular speakers. Both are Purist fluid cables. Solid state equipment.

and for many who believe in cable burn in, we don't listen to the cables while they burn in for a week, so it's not getting used to the sound...

I prefer the sound of non "burned in" fresh cables so I can only listen to them for a short time, and have to either swap them out for new ones every few days, or simply disconnect them and replace them from a pile of identical cables that have sat around losing their mojo. I need to find a burn in reversing device that sucks the life out of cables, not unlike what this post might have done to this thread.