The way I see it, engagement with concepts that you have fully understood is meaningless in that you’ll only marvel at your ability to understand things, rather then come up with a new insight from the engagement.
But most of the time, we don’t actually fully understand things, and intimately reflecting on something will often yield new facets, insights you didn’t have before, and deepen your understanding.
Maybe I didn't make myself clear enough. I read all kinds of philosophy (time permitting!) and it certainly doesn't have to be novel. However, when a philosopher adopts a rhetorical tone, I expect there to be some kind of catalyzing payload to justify it. Is that not reasonable?
I'd say truth is always being either discovered and recovered, and there's usually not too much difference. There's rarely anything new under the sun.
The truth, once discovered, ceases to be new. Does that mean the truth is not worth anything after an initial moment of discovery? Or (this is rhetorical, obviously), is it possible that the things that our mind tells us are worth pursuing/engaging and those things that are ACTUALLY worth pursuing/engaging are not always (or even OFTEN) commensurate?