The only thing I'd be worried about (aside from catastrophic events like lightning mentioned above) is the LCD burning out. I don't know how likely that is, but I have heard about a few people that have bad LCDs and who knows what the cause is..

For what its worth, my mac has no issues with me turning my 11r on or off, I usually have things going through built-in audio unless I am recording, and it always seems to recognize the 11r if it is on. Knock on wood, I haven't had any issues with the 11r. I am running yosemite on a mac mini and I am always going in through one of the usb ports on the back, not a hub. Maybe that helps..