1) keeping an additional TL, and some additional AAoA protection (but waaaay down the road, yes it is UP to ten years, and in some cases more, but in most cases it is at least several years),
As I think more about this, it occurs to me that you are leaving them open, not for now, but for protection later, as you state.
Ideally, one can control their situation and AAoA, but perhaps something happens and 10 yrs from now, you really wish you had that extra few cards with 120+ months on them to keep your AAoA high. I'm getting tagged now on that on my score. I could have had 5 good cards over 15 years on there to offset these recent apps.
In other words, it actually drops off your report when you may most want it and when it does the most good.
That being said, I would not keep everything. With a little effort you can create a AAoA trajectory and perhaps avoid cutting it too thin
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Exactly, my DH was suffering from closing his cc's 7-8 years ago and keeping only 1-2 'new cards'. Sure enough, when he did his one and only spree this March, his AAOA went from over 5 years to less than 10 months. If he had kept 1-2 more cc's open it would have helped. He had no idea those accounts he let close or he closed in 05-07 fell off his report early
Wow, and I was upset when my AAoA dropped by a year!