AAoA is 8 yrs.
ETA - This is after a fairly major rebuild, with several TLs added in the last year. On TU, my oldest account was opened: 23 Years, 11 Months ago; on EQ, 17 Years, 4 Months ago.
Starting Scores for 2013: EQ 723, TU 735, EX Credit Sesame 751
Current Scores: EQ 748, TU 741 (06/01/2013), EX 743 (06/13/2013)
Goal Score: 740+ FICO scores
Take the FICO Fitness Challenge Silver Spade Garden Club Member - Last App: 03/04/2013 - No apps until Fall 2013
Cards: Cap1 Venture 6.4k, Cap1 NHCR MC 750, BankAmericard 1-2-3 Visa Signature - UCF Alumni Association 5k, Discover 4k, Citi Diamond Preferred MC 7.55k, Wells Fargo Rewards Visa 7k, Chase Freedom 5k, Chase Ink 7.5k, Amex Green NPSL, Dillard's Amex 7.5k, JC Penney 5.7k, Kay Jeweler's 5.1k
Mine keeps shrinking!!! 
It was 7 years, then 6, then 5, then 4.5... and now there's a big split between my AAOA and AAOOA, which is 5 and 2.5.
I got a lot of closed accounts that are old, which is keeping it at 5, but I have added a lot of new recent accounts in the last 3 years.
I know FICO only cares about AAOA but some of the FAKOs and internal lender scoring also look at or only consider AAOOA (Average Age Of Open Accounts)
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