I've decided to use an old 120 GB 2.5" Western Digital drive in a FireLite FW enclosure as my MacMini Time Machine drive. It works fine, but I am concerned that it will be running continuously as the FW400 port is always powered, even when the computer sleeps. I have heard conflicting comments in the past about leaving drives running, some say it is the best way to run them, others say it shortens their life. My only concern is that the drive is in an unventilated aluminium chassis sitting on a wooden desk, so effectively the only cooling is from above. Anyone using a similar set up, got any thoughts?