Even implicit ones - the unsaid queries that motivate the composition of the piece
what's included, and when?
as important: what's left out?
make everything a deliberate choice
Why write, if not to test an idea against your own specific qualities? To see if there's a reaction, some expansiveness or contraction.
They provide the substrate to thought, and the nourishment, encouraging the frontier to expand
Rough Notes
The heap
The outlet for stream of consciousness thinking
See what associations bubble up to the surface
See what resonates, what clusters, the affinities that form
The warmup
Quotes
For the sake of having an opinion, I say it's better to rearticulate someone's idea in your own words, to digest it with your own acuity, than to simply reexpress the idea as a quote.
Other than stating something factually: at such a time, such a thing was said
Refernce it, so motivated readers can connect with more writing that may expand on the idea.
But don't just repeat the statement verbatim. Connect with the idea, exppress it in your own way for your own audience. Make it available.