Run on battery whenever you need to and plug it in whenever you can. You can plug or unplug at any time, regardless of the charged percentage. Just make sure you don't run on AC power all the time, as your battery needs to be used regularly to stay healthy. This should answer most, if not all, of your battery questions:I just bought a new Macbook Air today. And I want to know that should I plug it in for charge all day and all night or just charge it maybe only when the battery runs out.
That is not what the link you posted says, and is very poor advice. You should not leave it on the charger most of the time you use it. That defeats the purpose of having a portable computer and is bad for the battery. Also, it is not necessary to unplug when you're not using it, as it will not overcharge. Read the Battery FAQ for facts.Leave it on the charger for the most of time you use it, but not for all the time. When your not useing it, pull the plug unless you need that empty battery to be fully charged next morning.