Might be a silly question: I have an 8GB USB pen drive, formatted to Mac OS Extended (Journalled). I use it for backing up text documents (8GB goes a long way). Is it ok to leave the drive permanently plugged into my iMac? I don't know what the life of these devices is supposed to be, so am I risking damage/failure by leaving it in? My computer is pretty much awake 24/7.