MDtR, what is your opinion on keeping a few "no annual fee" CCs open for a long time? Does that help credit score or chances of getting approved in any way? Based on my previous misunderstanding of AAOA, I thought having a few such CCs open for a long time would increase the AAOA, but in light of how it is calculated, it seems there is no benefit to the score for having long opened accounts.

Now the only benefit I can think of is to have such a card from the major banks you continue to churn with, for establishing relationship purposes.