I've been using an old Pixelbook for 3 years that I had laying around for an always on Home Assistant control panel (but with adaptive dimming that defaults so extremely low brightness to reduce heat until approaching it).

I noticed a few months ago that the battery has started to significantly swell pushing the back panel apart, but I haven't worked up the motivation to try removing it yet. From what I can ascertain from user experiences, it actually does boot sans battery but haven't confirmed, it would be awesome if that worked and would probably give me 5+ more years of usage.

So in my case, data point is that 3 years of 24/7 use/charging of an old laptop/tablet was enough to push it over the edge and finally swell. It's really a shame how so many otherwise usable devices that could be wall mounted turn into e-waste because they won't run without a battery. With USB-C PD a well-designed device should be able to get whatever power is needed on demand but manufacturers don't really have any incentive to future proof for the .01% of users like me who would benefit.