... what is Settling Time in cables and interconnects...

Moving a well broken in cable around ... it may need time to return to the state it was in before it was moved. Settling time. Not a big deal. A few hours at most for a very small change most folks would never hear, or notice.                     
But I do agree best to not move cables around.. The longer they sit, the better. But if you need to, no big deal. (IMO just some additional thing for worrywarts to ponder)                            

Worrywarts = audiophiles 😬

People who can hear it = audiophiles 🤗

I'm just another Newbee so what do I know. But I have to agree that a broken in cable should not be moved around. They (cables) are just like us humans. If we settled in on a nice place, never move us from there. Same goes for interconnects. Don't change the right one to suddenly bear the left signal.
Sorry, if I got something wrong.

"I get my cables from unused NASA surplus shuttle maintenance stores that have been flown into space because it gets exposed to beneficial quantum radiation particle bombardment, then I have them professionally massaged in an oxygen free hypobaric chamber as the connectors are attached. I must say that bathing the cables in liquid nitrogen just prior to every listening session really sweetens the sound too, but sometimes my cat gets it's tongue stuck."  

Cables, breakin time, OMG,who has time for this hobby. I would think if you turn on your systen and it does not sound good, get some speakers, a amp,or a new cd player, or a new life! I have been in audio for 30 yrs and I read these posts and cant help but to think we are putting too much effort into this insanity. I am also guilty of trying to achieve audio perfection but as we try to chase this insanity, if any abstract audio improvent idea sounds like something that will change our lives. Trust me,,,,it dosent exist! If you need a new sound,,,change something meangingful in your system,,,or get a new life!!!!!!!!