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My personal take is that birds are much happier and healthier flighted. Research shows that clipping before fully fledging does permanent damage to the bird, but yours are adults.
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I've been trying hard to keep my tongue in cheek here, but obviously haven't quite succeeded. :54:
Both Niko AND Ripley were clipped (badly) before fully fledging, and there is absolutely NOTHING wrong with them now.
Niko is 5, and yes, it took almost 3 years until both his wings were fully grown out since he continuously had accidents when the flight feathers were coming in, and they'd break off, often even resulting in blood loss.
He is a VERY skilled flier now. So much so that he can turn on a dime in mid air. He is also VERY social and VERY well behaved, so I'm quite curious as to how exactly he is 'damaged'.
Ripley was 1.5 years when he came to live with me, and since I know where he was raised, I also know he was never allowed to learn how to fly properly. It took less than 6 months for him to grow out his flight feathers, and he's been making excellent use of them ever since. He is equally well behaved and well socialized.
Earlier this year I had a frightening experience with Niko. While out on his playtree he was massively spooked by 'something' and he crashed into my big window badly. A window which he had never crashed into before, a window he 'knew' to avoid. I can only figure in his panic mode he didn't realize there was glass separating him from the great outdoors, but he smashed into so hard, he had a bald spot on his head.

I am still counting my blessings that I didn't lose him that very day, as he could have just as easily broken his neck on impact.
I clipped ALL my birds shortly thereafter. Just enough to prevent panic fliers to make it quite THAT far. And we had a fantastic summer, spending lots of time outdoors.

None of them held a grudge or showed any signs of stress or other ill effects from being clipped.
By now each one of them is fully flighted once again, and I'm planning on keeping it that way throughout the colder months.