Depends on the actual usage patterns, whether you keep it charged at say 100%, 80%, 40%, etc; its temperature (hot=bad), age, number of charge cycles, technology, how often you actually unplug it, etc - but yes, if you mistreat it, it can get dangerous.
My old 2017 MBP met that fate after mere couple of years, these machines tend to run annoyingly hot (I can hear it right now from the other room - partner is still using it). When it was mine, I kept using it with the lid closed (because the internal screen+keyboard were useless to me). I totally wasn't expecting the battery to suddenly become a spicy pillow! The Apple tech was a little bit scared to touch it, said it's gonna take a while to repair, I guess they can't open this sort of thing on site.
Of course some things changed with M1 (less hot) and later macOS updates (smarter/delayed charging), but the general advice applies to literally any device with a battery.
That's not my experience for almost any recent (last decade) laptop I've owned (or used for work). They pretty much live tied to a charger, but I occasionally move them. Some battery degradation but all had decent battery for 5+ years. Note: all of them were Macs.
What is the mechanism by which you think that'd happen? My understanding is that if you did that, the macbook would stay 80% charged and would use the power supply directly to power itself.
So the battery stays about 80% charged and gets topped up to 80% intermittently when it naturally discharges. Is that not basically they optimum case for battery longevity?
I have never heard of this functionality. Is this some magic setting somewhere? When I plug in my MacBook it charges to 100% and stays there. This isn't a Tesla: this is a laptop. When the pandemic started and I stopped traveling the battery in my MacBook very rapidly nearly fully died.
Regardless, all of my MacBooks eventually have battery problems whether they were plugged in all the time or not: it is extremely common for MacBook batteries to eventually get so damaged they start to swell and either need to be replaced or crack the case (and that's ignoring the fire hazard).
I'm pretty sure that article is talking about the feature where, if MacOS realizes that you always plug in your laptop at night, and unplug it every day at 7 am, it will pause charging at 80% until like 5:30 or whatever time it needs to, such that it will reach 100% exactly at 7 am.
Right, it tries to guess and it's not very good at it. But IME if you do pretty much always use it plugged in as was being discussed above, it will just stay at 80%.
This hasn't been true for a very long time. You lose 15% capacity per year just like with any other lithium ion battery that you store at close to 100% charge.
For UPS applications you can use 3rd party software to force the battery to stay at 80% charge and lose less capacity per year.
I haven't found this to be the case. The OS is fairly intelligent about charging so this doesn't happen. Probably not ideal, but the flexibility is more than worth it IMO
