Okee dokee, all this debate made me look up the word in a dictionary which came up with the following meanings: 
 
 
vin·tage   /ˈvɪntɪdʒ/  Show Spelled [vin-tij]  Show IPA noun, adjective, verb, -taged, -tag·ing.   
noun  
1. the wine from a particular harvest or crop.  
2. the annual produce of the grape harvest, especially with reference to the wine obtained.  
3. an exceptionally fine wine from the crop of a good year.  
4. the time of gathering grapes, or of winemaking.  
5. the act or process of producing wine; winemaking.  
to wines or winemaking.  
8. being of a specified vintage: Vintage wines are usually more expensive than nonvintage wines.  
9. representing the high quality of a past time: vintage cars; vintage movies.  
10. old-fashioned or obsolete: vintage jokes. 
 
Good thing is it majors on wine, a little bit like the missus so maybe she will also become vintage.  Also note meaning number 9, which does fit into there being a period in time where the item being referred to is accepted of being of higher quality