Shadow of The Wind
Some people still believe that leaving devices on all the time is good.

Some people believe that devices should last forever<G>...
 

Shadow of The WindThe opposite is true: heat kills components. (I am not talking about not using gear for years.)

Heat does kill components. But so do transients, which was the rational for leaving gear on all the time.
 
Gear dies...
 
I have three Frontier Design Tangos... I can't remember how long I had the first one before it failed, but it was many years. I left it on all the time. I added two more, and for some reason decided to power down that rack when it was not in use. All three Tangos failed within about a month of each other.
 
Coincidence? I have no idea!
 
Lucky for me it is easy to repair them! This time around I used components with higher temperature ratings, I still turn off the rack when I'm not using it, I'll be curious to see what happens<G>!

... then the current literally melted the male pin off the compressor's power plug. It looked like it was a welding rig.

 
Similar thing happened to me a couple weeks ago.  I was using my multi-meter to check my electrical panel and accidentally touched a 30 amp circuit.  My probe was instantly vaporized and multi-meter blown.  
 
It is very unlikely phantom power damaged your preamps.  But it is good practice to turn off phantom power and wait a good 15 seconds before unplugging condenser microphones.  Connection problems are usually the No. 1 cause of signal failure.  Capacitors can also blow if there is a power surge and improper current protection.  Keep in mind cheap gear will not last, Zooms break easily because they are built like toys, M-Audio is a little better, but not much.  Probably isn't worth trying to fix it as that would cost more than a brand new one.  

I turn my gear off to save electricity.