Display Cable: 2015 12"(MacBook) + all 2016-2018 Pro models experience issues with display cables failing after normal use. This is because the cables are built weakly and they become damaged from opening and closing the display lid. Ive already had to replace displays on every model except the 2018 air, but that one came out only few months ago so im just waiting for them to start failing too.
Most common symptoms also include display showing no image, display backlight only working when display is opened to a certain angle, or any sort of video artifacts that persist on the display. The stage-light one actually isnt as common as the display showing no image as a whole.
currently there is no program for this meaning that if you have no warranty (applecare+, limited warranty, or consumer protection laws) then you will get charged for this defect!
If the display cables fail, it's $600USD to replace the display. there is no "cheaper" aftermarket solution, the cables are a part of the assembly
Keyboards: 12" 2015 (MacBook) + all 2016-2018 Pro models will develop keyboard issues eventually, its a matter of time.
2016/2017 (and 12" 2015) have the extended keyboard warranty program
this program covers these units for 4 years from original purchase date meaning that 2016 models coverage ends around 2020/2021 (depending on exact purchase date) and 2017 ends 2021/2022. 2015 12" is ending between this year and next year, so 2015 12" owners be prepared!
2018 is not covered by this program. They rely entirely on their warranty or consumer protection laws as of right now, meaning that if you didnt purchase applecare+ or live on a country where CP laws suck, youll only get support for 1 year out of the box (with a few notable exceptions like Turkey).
For any of the above, once your warranty or keyboard coverage ends, its $600 per failure to replace the entire top case. there is no "cheaper" aftermarket solution, the keyboards themselves are a nightmare to replace and the aftermarket parts are even more likely to fail
In both scenarios above, replacing the part will not permanently fix it since they only replace it with identical parts, meaning theyre bound to fail again. Plus all machines will be classified as vintage 5 years after their original release date, and once that happens spare parts go bye bye for good and youll be left only with the cheaper aftermarket or used parts. If youre looking for a reliable macbook, stick to 2015 pros and any 2010-2017 air. If you havent bought applecare+ already, buy it now