Since my mobile phone starts charging automatically every time it is connected to the PC via USB cable, I was concerned that this would damage the battery in the long run (I do data transfers via USB quite often). But then I read somewhere (cannot remember where, but was a reliable source) that, because the battery is Li-Ion, it does not care how often you (partially) charge it, and whether it is full or not when you unplug the charger. So I continued to connect my phone anytime I needed to, without worrying about the battery. Recently, my laptop charger's jack got dented, which made it cling only very feebly to the laptop, and thus unable to provide continous voltage to the PC. This meant that when I moved the laptop around, I would constantly hear the beep that the PC makes when the charger is plugged/unplugged. Since I did not have time to get another charger, this went on for a few days and completely ruined my battery, to the point where now the laptop won't last even 10 minutes on battery. So apparently, frequently plugging and unplugging the charger tremendously shortened its life - which made sense especially when I remembered the classic recommendation of not using up "battery cycles" by unnecessarily plugging and unplugging it all the time. This is what got me confused. If my laptop's battery (which is a Li-Ion, just like the phone's battery) has died after a damaged charger rapidly - and many times - connected and disconnected it from AC voltage, why would the phone's battery not be affected by me repeatedly connecting and disconnecting it from the power supply whenever I make a USB transfer? I would very much appreciate it if someone who understands how batteries work better than I do were able to clarify me on this - many thanks in advance!