I'm an undergraduate who is going to be a Ph.D candidate this fall. After reading papers extensively for writing the literature review, I realize details in some papers, though I totally understand them at the moment I read them, are almost forgotten when I try to cite these papers.
I wonder what's your habit to keep track of the papers you've read (for long-term retrieval).
If you want to remember something long term, spaced repetition is a good way to remember it.
I interact with hundreds of papers per year. Trying to remember them all is futile. You should prioritize.
There are various methods to keep track of your readings; a spaced repetition is not necessarily indispensable.
My preferred approach is: to annotate, to collect excerpts, and to tag these excerpts so that one can find them again when one searches by keywords.
Citation managers such as Zotero offer these functions.
I personally use a digital 'Zettelkasten' (TiddlyWiki) for this purpose.
Both Zotero and TiddlyWiki are open-source and free.
Statements that are not excessively technical can be written in the appropriate Wikipedia article, while citing the article as a source. To some extent, Wikipedia can thus be used as a shared guide to the literature.
Of course, you need another solution for the technical details and personal annotations: see the other answers.
