The good old days...
Historically, the most common usage of the word was in reference to the year of origin of a bottle of wine.
Etymologically, it literally refers to wine - to the harvest of grapes. It comes from the old French word "vendage," meaning "yield from a vineyard," and is some 700 years old. (See Online Etymology Dictionary, if you want more details.)
Over time, it took on a positive connotation. In most conversation, "vintage" was a reference to an exceptionally good wine rather than merely an identifier of its production.
Nowadays, the word is frequently used in reference to an older automobile, as a substitute for "antique" or "classic."
For much of the second half of the 20th century,