Great post with lots of info. I have had my laptop for many years.
One thing I found is never let the battery run completely down. I do not know if that is possible for you but it helps keep from getting a new one. That is after you get your next new battery.
yes, the battery should remain 15% before we plug it to the power source that is the ideal thing to increase the live of it @rebeccabe. but something getting electricity is real problem in my place. It wont be a short time to get new battery LOL. that is not a big deal at all, the first priority is basic needs
I say plug in way before 15% ...
anyway, you are right basic needs first