I’m not really quite sure if I need to drain all the way the battery of my iPhone and my digital camera before charging them. I’ve searched online and found conflicting results so I just drain them before charging eventhough I have a bad experience with my laptop battery before. I drain the battery and charge it afterwards but too bad, I left it still on the socket and I guess I might have over charged it that’s why it only lasted for a year.
There are also lots of batteries like ls 14250 that are designed for longer use at up to 20 years. Ahhh.. wished I have used one of these lithium batteries before that I might have saved money also.