How long for an HDMI cable to break in.

You won't ever get any consensus here, but if you don't hear a distinct improvement for that kind of money, I would return them if possible-certainly wouldn't wait for the sound to change and burn your return period. Trust your ears as they say. 

Gee, I thought I would get a simple answer for a specific cable that is known. Like 50, 100, 150 hours like an amp. And why would it have arrows when there is no difference in direction. There is even no bling in that.

@kevemaher 

I re-watched that video.  It confirms what I wrote:

Complete a circuit, and there will be a slow electron drift on average from negative to positive.  The electrons flow in the circuit.

Now would you like me to correct your assertions that:

Electron motion and electromagnetic forces and energy in circuits are determined solely by the electromagnetic fields generated by a difference in potential

@invalid 

My amplifier shorted out and several photons shot out

My Krell just let the smoke out ...

I’m terrified to jump into this lively discussion but I have a 1 meter hdmi going from my transport to my dac for I2S.  How would I know if the length of the cable was an issue?  Sound degradation?   It sounds great but I’ve seen a couple of times now that a 1 meter HDMI for i2s can cause issues but nobody says what this issues could be.