I'd be inclined to says its old school. This day and age the batteries are not memory thereforee you can charge again from 40/50/60/70/80/90% and the battery stops at 100% it doesn't memorise this like "old school and then after charging without draining causing the battery to not complete a full cycle which in turn malfunctions it, because they got charged and charged from the same spots over and over again without giving the battery a full cycle. Batteries have advanced immensely since the late 90's. The iPhone 4 & 4s work in the same way.
Then again I could be wrong. (I don't make them) it's just my thoughts.
Calibrating is definitely a good way to prolong battery life. Many others have rec'd before --download coconutBattery app to which helps you keep track of your current charge & capacity in comparison designed charge & capacity.