When I'm in front of the computer, I always keep my Android phone plugged into a USB cable so it's always at a 100% charge and I can type text messages from the convenience of my PC keyboard.
Still, I was wondering if charging a battery when it's already 100% charged hurts: Will it "wear out", ie. won't hold as long?
Generally speaking, is there a good article that explains how to charge and use the main types of batteries? For instance, I seem to remember that some batteries must never be left below 20% charge.
FWIW, I upgraded the original battery in my Samsung Galaxy Nexus to a slightly bigger Li-Ion 1900mAh.