Some clarification: I have an external HDD that gets it power from the USB port. Even if I turn of the computer, the HDD won't shut down, because there's power-off charging on that port. This is my only USB3 port, so using an other port is not an option.
Mobil 1 Extended Performance synthetic oil is recommended for oil change intervals up to 15,000 miles or one year, whichever occurs first. However, if your vehicle manufacturer recommends an oil change interval beyond 15,000 miles and Mobil 1 Extended Performance meets the performance level specified, you can be assured that Mobil 1 Extended Performance will go the distance.
Re: Low mileage oil change. On the newest car (2010) with about 70K miles on it, I use synthetic oil and change it at about 8K miles, which takes about 7 months as it's our long distance vehicle. The 2004, which my wife drives, is local use only and has right at 20K miles. It gets regular oil and is changed once a year at inspection time.