Having repaired many C/Ps over the years the component that most...

Having repaired many C/Ps over the years the component that most often fails is the Power supply, (which can easily be replaced)

After that it is the software which can usually be re- installed
Then there is the bad connections (from the slide in contacts internally) and physical damage

Power supplies on other electronic items also suffer the same fate

Electronics as a rule last forever unless abused