how to properly charge battery?

[lruggier]

Ok, one last question for you all, when I get my new battery should I:

1.only charge it when it gets to 10-15%?

or

2. should I still charge it whenever I need to charge it up to 100% no matter how much battery I have left since its a Lithium-Ion battery and it will be ok if I do that and I can leave it plugged in at 100% if I want to because it does no harm to the battery since there is no such thing as over-charging a lithium-ion battery?