I've been looking around for the last couple days for information about how often to take the rmbp and cmbp off the charger and how low to discharge them before plugging them back in. I found several threads here, on google, and in the apple support forums. Here are some of the articles that I read: http://www.apple.com/batteries/notebooks.html http://www.bigbruin.com/2007/battery_1 http://www.apple.com/batteries/ http://docs.info.apple.com/article.html?artnum=86284 http://batteryuniversity.com http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries The problem is that none of these articles or the other threads I found on this forum actually give a number for what percentage you should let the battery reach before plugging it back in to recharge. I will mainly be using my rmbp as a desktop. Because of this I will be able to keep it plugged in most of the time but I know that without being used, the battery will degrade more quickly. This is the only apple discussion support post that I could find that mentioned a percentage but it wasn't given by someone at apple: https://discussions.apple.com/thread/4185138?start=0&tstart=0 What percentage should I let it run down to before plugging it back in?