I have something like 1500 papers on my PC and it is hard to keep track of all of them. I've painstakingly organized them all into about 10 categorized folders, and named them all by first author's name + title + year. I then put it all in cloud storage so that I can access it anywhere and don't have multiple copies of the same article. And every time I finish reading one of them I update a summary/review of what the paper's about on a bibtex file, otherwise write down my own notes in a single large LaTeX book. But it's still rather hard to keep track of it, and I wish I was spending less time doing manual labor with arranging the journal articles. What do you guys do to organize your papers?