Leaving macbook plugged in and on 100% all the time So for the past few years, I've been under the impression that with any modern macbook (e.g., 2015 and later), it's better for the battery health to leave it plugged in as often as you can since the battery deteriorates based on cycle count, so if you leave it plugged in, it's not using the battery and thus not increasing the cycle count. Then I saw this article from last summer https://www.macworld.com/article/3564563/dont-keep-your-mac-laptop-charged-to-100-percent-all-the-time-heres-why.html that seems to contradict what I've seen suggested the past few years, which is recommending that your unplug your laptop daily and let it drop to 30-40%.
So I am confused on what advice to follow. Each dichotomous suggestion seems to have a basis, but which one is valid?
The Macworld article reflects best practice.  The battery is designed to be used.
I wouldn't be too concerned about dropping the charge to 30% every day.  Even dropping to 80% will help.  For a long healthy life the battery should be used.
Of course, if you keep it plugged in all the time you don't have to be worried about keeping the battery healthy!
Just to say it again: The battery is designed to be used.