Most people do not need to know anything
Most computers I have built are still working some 10 years old or more. I always give the buyer a set of applications to keep the system clean and tidy and they always come to me if they have issues. A good 80% of the machines I have built have only ever had software issues the rest perhaps a dead hard drive failed memory mobo or PSU. I have only ever had 2 or 3 dead cpus.
(figures pulled out of nowhere so most likely bobbins lol)