I age all of my tobacco as most of my cellar consists of Virginia, Virginia/Perique, Virginia/Burley,Virginia/Aromatic Flakes. All of these except the VA/Aro's can be aged forever and they keep getting better. I don't have any experience aging VA/Aro flakes as I just began cellaring those in the last couple of years. I am assuming that the Aro flavoring will start to minimize too much after maybe 5 years or so. I will keep checking my stock of Aro's every year to see if I am losing flavor.
I do have a half dozen of non flake aro's that I don't plan on aging like I do my flakes. From what I have read, aro's will lose flavor after a certain point so I will be watching them closely.
Also if you read Sabblebrush aka Jesse's link to a Greg Pease article, don't take it as gospel. I have forgotten more than Pease knows so listen to me. :nana:
ps: Be careful about aging English blends as they will lose flavor after a certain point. I don't smoke any English blends anymore so I am not sure when they start to lose their flavors.