failing to repair known defects

you mean the whole card or an onboard chip?

I think the circumstances mean everything, why should they pay for it
if you spilled a drink on the PC? Or you tried to overclock it and
burned it out?

Also depends on age

I have opened up PCs before that have burned up that had so much dust
on everything it was a wonder it didnt start a fire. I wouldnt pay
for that repair either, people need to take care of their stuff.

That would be ridiculous, as it means the consumer has no obligation
to use common sense.

I just had a dell come into my shop that dell depot repair had
returned to the customer unrepaired I asked her why, and she "did not
know it still kept getting really hot and crashing" I opened the
machine enough to remove the keyboard, I saw the dead roaches inside
when I told her that I could clean the machine, and replace the
motherboard, but she would also need to pay for an exterminator for my
shop she refused service