I've got a few Dell 17" Laptops which I too keep plugged in all time. One is nearly three, the other nearly two years old. When I take either one off the charger... over to the easy chair or couch, they run for hours off their batteries. I have read similar articles all claiming by keeping it plugged in will shorten battery life. Although, I'm still waiting for this to happen. More than any other factor, I think heat will kill the battery faster. Regular batteries are inexpensive, so I say why worry.