lomapaseo
I was using the word premature in the sense of earlier than expected. Whether that is measured in simple engine running hours or cycles would depend on what is normal for the particular engine.
By 'certain' contaminants I was referring to those that at HPT blade temperatures change their nature to a 'glass' like material that has been known to flow and coat surfaces.
Sadly I think this whole situation is one of those 'where we know what we don't know'
I would not like to be thought of as a doom-monger just as somebody who does not know enough to make a flight safety based commercial decision on this topic - sometimes it is great being retired!