Issues to look for with used 2012 15" Retina MBP?

[147798]

I did some research, and found a number of issues w/2012 15" rMBP, but many of those issues might have been resolved with FW fixes, etc.

At this point, what are the major issues one might face in purchasing a used 2012 15" rMBP?

I found notice of Apple extended warranty, but in buying one used, 4 years later, I wonder if that would apply to me??

 

[robvas]

Screen retention issues, video problems

But really just look at all the standard stuff, is the screen coating peeling off, do all they keys work, is the battery good, dent free case, do the ports work, does it sleep/resume properly, is the power cord in good shape, does the speakers/mic/webcam work