I've heard varying stories regarding aging of whiskeys. Some people seem to say that aging past 12 years is silly, and that the whiskeys we find charming after 18 years would have been just as charming after twelve, but are better quality whiskeys to begin with. That is, the whiskeys selected for extreme aging are in fact a better product in the first place.
To add to this argument, I've read that term in barrel is far less important than the quality of a barrel - a fourth-run sherry cask cannot impart nearly the flavour of a first-run cask, and the "maturation potential" of the latter is better.
Any thoughts?

