It is important to create a shit tag (literally), to keep track of songs to delete.

When looking for songs in the library, it's very important to answer a few questions to filter. Not just to save storage space, but also to ensure the quality of one's library.

Chris M. recommends a SHORT LIST... Music you come across that you like and think about downloading, you put in there. Then wait for 24h before listening again to it. Finally, ask 3 questions before deciding to add it: - 1) Do I still like it? - 2) Would I play it out? - 3) Would I pay money for it?