I would say easily a third the time I need a paper, I&#x27;ll have to get it through Libgen, and especially if a paper is new or published through Elsevier or Nature. (If you&#x27;ve read through my comments and noticed me posting Dropbox links to fulltext PDFs - Libgen in action.) It&#x27;s also good for older papers pre-2000 where it&#x27;s unlikely the author has put up a copy or someone else has hosted it, and finally, it&#x27;s good for getting finalized copies of papers as published since preprints often change quite a bit (economics papers in particular seem to spend years hanging around going through many versions which can change conclusions dramatically).