[gtirloni]

I've replaced the batteries on several phones (at authorized places) and, while I like the idea, they all started displaying weird behavior. I guess they are glued so hard that the heating needed to open them up must cause some tiny damage. Just a guess.

[andrewia]

I haven't had any issues with a Samsung S7, Samsung S9 (although I broke HDMI output), and Sony Xperia 5 Mark II (very pleasant to repair). iPhones have been much more troublesome for me, as I have destroyed three during repair attempts. All the issues were from damage to ribbon cables, as they are fragile and easily damaged from being bent. So I'd advise avoiding devices with tight tolerances like iPhones, and minimizing interaction with ribbon cables.