Lurker, A port wine that has been filtered then bottled will never get any better.The unfiltered ones can improve for decade. They can also increase drastically in value. It was and maybe still tradition to buy a bottle or case of port vinted in the year of your sons birth. At age twenty the father would open the bottle and drink it with his son. In the case of buying a case, Old dad would give the case to the son at age 20 to enjoy throughout his lifetime. Expecting for him to drink it on important occasions and keeping at least one for retirement. Fine ports are not expected to be touched for at least 20 years. Now that is pushing the three Ps to the max.
Brad