For anything but a really highly strung competition bike, component failure due to age/use (other than wear items such as tires, cables, drivetrain) is very unlikely excepting neglect, abuse, or improper adjustment. Putting that another way, a properly set up and maintained non-competition bike should not be experiencing base component failures except with very high mileage. If such failures are occuring at low mileage, it is probably due to a low grade/defective component, or some external factor such as neglect or abuse.
If you have concern about known or possibly high mileage components or ones with dubious heritage, it would be wise to bestow on them all reasonable preventive maintenance and inspection procedures, before entrusting them with your safety.