Care and feeding of batteries

I hear a lot of conflicting advice about laptop batteries. Some say I should keep it topped up at 100% and then let it drain all the way down once a month. Others say that charging it once a day is better. Who is right? I use my MacBook Pro as my main computer and it is normally plugged into the mains on my desk. But I want to have the option of running from battery occasionally, such as on holiday. George Peake Lithium-ion batteries don’t like extremes. They don’t like getting very cold or very hot, or spending too much time in a completely flat or completely charged state. Indeed, Apple’s advice at apple.com/batteries used to say of its lithium-ion polymer batteries: “If you don’t use your device often, be sure to complete a charge cycle at least once a month”. That exact text no longer features on the site, but Apple still recommends charging your MacBook to 50% if it’s going to be stored long-term.