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

Hi sejodiren :-)
Dont forget the effect of suns radition & beam angles in different seasons.  That also affects the sound tremendously.  I hear the BEST sound usually on 21 June between the hours of 11:00am and 17:00pm in relative humidity of 78% :-)

Here’s my take on the OP’s question.

Settling-in would generally mean that a broken-in cable needs a brief period in an audio system to settle-in before sounding optimal.
If a cable has not had signal for a long period of time it may need a longer time to either, 1. break-in again or 2. settle-in.
Some define break-in and settling-in as the same thing although generally break-in would take a longer period of time.
Some reject the whole notion as ludicrous. Thus the collective groaning when this thread was posted.
As a newbie I see no problem in asking the question but be warned, the answers can be contentious and divisive (and occasionally vitriolic) so the wiser here tend to avoid the discussion altogether. Of course there are always those who are itching for a fight.
Hope this helps.

Is it so then that if I only disconnect the speaker cable for a very short moment to change to another speaker, I only need to give the cable the shorter settle-in time of maybe twelve hours before I with conficence can evaluate the sound of the second speaker to the first speaker. I really would like to get this right.

If burn-in by manufacturers works, then the positive effects must last several days to allow for shipping.
I don't think you need to worry about minutes or hours or even a couple of days.
Once any cable is physically moved, it needs a little time to settle once it is back in action again, so the gap period isn't crucial.

1. I never suggested anyone should worry about it.
2. I was merely attempting to provide a definition for the terms.
3. I think we should all listen to gosta if we have any audio concerns.
Could it be that many of us are listening through signal cables that are not adequately burned-in?
Perhaps a device like the Audiodharma could change some opinions.