I just spoke to Scott Labs and Lafatite about the aging capabilities of their natural corks and got the same answer from both. I spoke to them because they are the only 2 places I know of that would be a reliable source of information. The response was 6-8 years and 5-7 years respectively no matter what the grade was and the only difference in the grading is the appearance. Now I don't know if there is any truth in what they said but to get the same answer from 2 reliable sources leads me to believe what they say. Although in my mind I would think the higher grade would allow the wine to age longer. But why would they say this, in a way it's telling me to buy the lower grade.