I think # 3 would be closest.
Except that I would expect DIGITAL components to fail before audibly changing.
And PASSIVE components would be the most likely to
drift before failing.
80% of all PCB failures are do to solderjoint problems. When the components with the solderjoint problems are replaced they have new solderjoints and most of the time the problem is blamed on components. Not true.
As far as tubes go.. I cant comment.. I dont know reliabilty. I do have tube guitar amps but havent heard a audible difference yet and no failures.
I have had audio equipment play the same (not very well)
for 20 years.
So the answer is all of the above.
Except that I would expect DIGITAL components to fail before audibly changing.
And PASSIVE components would be the most likely to
drift before failing.
80% of all PCB failures are do to solderjoint problems. When the components with the solderjoint problems are replaced they have new solderjoints and most of the time the problem is blamed on components. Not true.
As far as tubes go.. I cant comment.. I dont know reliabilty. I do have tube guitar amps but havent heard a audible difference yet and no failures.
I have had audio equipment play the same (not very well)
for 20 years.
So the answer is all of the above.