Question:What is the best way to use my computer regarding its battery: should I plug it into the wall or should I run it off the VGP-BPL2  battery even when I dont need to?

   Answer:I'd say plug it in.

Newlaptop battery don't have the battery "memory" that the old ones do. It is no-longer necessary to fully drain it to get the best charge.

The power saving features won't shut you down for walking away if you are plugged in. If unplugged and you get a phone call you may come back to a hybernating computer. If you're by an outlet there's no reason to deal with it going to sleep on you.

Also depending on the laptop, it may perform up to 50% faster when plugged into the wall because it doesn't have to worry about clocking down to save new sony battery  life.