My oldest stick is a tiny figurado from Germany that was made in 1930s. Was gifted to me at TriSheilds herf last year. Also have a couple from 1948 gifted to be my Scott (Shilala).
I have had ROTT LP #9s and some with a few years on them. While they are very tasty ROTT, they lose a little bit over age, but that won't stop me from keeping them in the humi.
One brand that I truly believe gets better with time are Olivas. Anything Oliva holds up to some time. Prime example is the Blue Cloth Bands...they are FANTASTIC!!!