i searched on this based on the drive i want to get, but did not find anything that addressed my specific question... i recently got the latest airport extreme base station, and since i have leopard and time machine is now possible with a usb drive plugged into the router, i wanted to give it a go. i'm eyeing the western digital passport (portable) drive - i figure it would be handy to have a portable drive in case i do find the need to take it out and about with me at some point. however, would it be bad (i.e., subject the drive to drastically more wear and tear such that it would fail much sooner than normal) to keep this drive plugged into the ae base station constantly? i know that the base station can power a usb-powered drive, so i'm not worried about that. i'm just wondering whether or not i should lean toward a standard external drive with its own power source and fan given how i'll be using it... any advice would be greatly appreciated!