How many times can you zero-life ac components? Surely there is a limit.
I don't believe there is. Most of the aircraft flying over your head right now have:
1. Zero-timed components
2. Re-manufactured compnents
3. Re-conditioned components
4. Second-hand components (inspected and issued a Form 1)
I think, with all the modern non-destructive inspection techniques applied to newly manufactured or re-worked components, it would hard to fault the process. In fact, this kind of inspection has revealed issues way before failure that would have been missed before - thus you could argue that the practise makes flying safer.
Finally, if you took the old KC-135Rs and dismantled them into their metallic components, then melted/smelted them, rolled/milled/cast them and then re-assembled them back into a KC-135R then you could run the risk of introducing manufacturing defects not present before!
I think it is time to trust the re-use of properly re-manufactured and/or inspected components and to stop be-littling it. If we have some significant losses because the system starts to fail, then stop it, but at the moment I can't think of any major losses attributed to this practise.
LJ