Beer aeging

With the discussion on the Orval from today, i wonder what your experiences are with beer aeging.

I can share mine and maybe I can get some hints from the community:

Orval: My personal preference is about 6 months old, when the hop taste is not as strong as fresh, but still enough dryness remains. I have drank Orval up to 10 years old and found it going slightly too sweet or chemical.

Sint Bernardus Abt: I have drank that up to 10 years old. I prefer about 5 years old as it is a nice equilibirum between young beer and the typical burgundy oaky taste of old beer.

Kasteelbier Cuvee du Chateau: The older the better. This one becomes an absolute tastebomb at ages 10 years and more.

Blonde beers generally don't evolve as nicely as dark beers. I have tried Karmeliet, Westmalle tripel, Chimay blanche.