I found that I was only interested in a few thousand albums of classic rock from the 1960s and 1970s and a thousand films. I've made copies of them from the public library DVDs and CDs.
I believe that making copies of works that you do not own individually are not covered under fair use.
Grandparent pays taxes. Taxes support the library. Library buys books, movies and music to make them freely available to the community. If the RIAA/MPAA don't want their products freely available like that, they should stop selling to libraries and/or sue them for lost sales.
It seems that more and more mathematicians are using a new, high level language named "research student".