Should the power be off every time changing cables?

Playing with electrical components -always best to play it safe. Power off.

Real world-I've never been to a demo/show, where gear was turned off, with the exception of power cables.
This has been with the presence of the amp/gear designer standing next to their creation.

https://m.youtube.com/watch?v=byVrloNIcKQ

Volume down, source not playing, obvious precautions.
Also experienced hot swaps with side by side speaker comparison- music playing, quick swap of speaker cables to hear differences. 

Living on the edge!

Thanks for all advice.
Normally I turn off all gears before changing any cables, but I am about to play around with different speaker cables and IC cables with different power amps and preamps, and found out that it is hard to compare the sonic differences before and after changing cables if I power off, wait for a few minutes, and then power on.
I will follow the safe route most of times, but if I need to, I will change cables with preamp set to mute and input selector set to an unused input.

by switching the input you protect speakers not amps.
by turning the power off you protect everything .
the choice is yours 

Another voice from the "turn the system off" camp.