This is about purchases you should have given more thought in 2017 to present.
For me it was everything from Sample from Mars.
I like multi format libraries. I created refills, added them to Live's library which has no compression and comes up with errors. All the Kontakt one's I batch compressed. After auditioning the synths I'm not sure I could ever really use them. As for drum samples I probably have duplicates in other libraries. Using 3 formats really used up a lot of drive space.
My second system has 2 separate 1TB storage drives, 500MB drive and one (1tb) actually showed red in Windows. I started thinking I really didn't need this.