I wonder how the queen is feeling tonight. (Strangely, and for no reason, I've been humming her song the last couple of days. I wish her well, btw; I think she's done a better job as monarch than the vast majority of her predecessors. But every era must end.)
I'm not so sure about the patience of age. So many elder parts are bad at waiting for things, and so many of us have a tougher time every year, suffering fools and wastrels. I do see the need for rejuvenation.
What if you had alternate bodies? Clones would do in a pinch, but I'd prefer a real change: five years as an iguana, perhaps, then back to my regular self for ten; five years as a Laplander, then back to my regular self for ten.... A change of scenery and perspective, different sensory equipment. I've always envied Granny Weatherwax her ability to 'borrow' other creatures. It wouldn't need to be actual bodies; it could be a virtual vacation in a computer simulation.*
But even if you didn't regenerate the physical brain, at least you could take on some long-term projects.
Of course, none of this is practicable with the current level of population or anything near it. It could only ever be available to a few. In SF mode: how this story would end is: Yes, they invent the anti-aging drug: people who take it stay the same age as when they begin treatment.... for the exact number of heartbeats they would normally have had left. Some good-looking corpses for the embalmer.
(* Yes, I'm aware that a computer doesn't understand the first thing about how being an iguana feels. But it could recreate the environment, locomotion, POV as well as it could for magic adventure games. I'm sure some bright young-ish coders would be happy to get on that project.)