Apple 自己都有講，就算衣家已用Li-ion都唔代表唔洗maintenance，
http://www.apple.com/batteries/notebooks.html
For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Apple does not recommend leaving your portable plugged in all the time. An ideal use would be a commuter who uses her MacBook Pro on the train, then plugs it in at the office to charge. This keeps the battery juices flowing. If on the other hand, you use a desktop computer at work, and save a notebook for infrequent travel,
Apple recommends charging and discharging its battery at least once per month.
即係就算平時長插濕電都唔係問題，但係最好每一個月用盡D電一次 (discharge)
