I never use all my storage. (Except when I was dual-booting on a 256 gig SSD lol.)
I currently have about ¾ of a TB of data. That includes a lot of pictures going back to at least 2017, a lot of music, a few games I could easily download again, and a ton of anime. Also all my system files, applications, and so on, backed up.
I'm not a quality snob (cannot tell MP3 from FLAC for my life, and even when I can tell I mostly don't care). I delete games as soon as I'm done playing them, and uninstall applications as soon as I don't need them. Keeping my PC in order is part of keeping my mind in order, and I guess my soul as well. My 3.1TB across three drives is already more than I need - don't know what I'd even do with 5, 10, or 20TB of space. I find storage setups fascinating, though - I know all the different forms of RAID, and love hearing about people's unique ways of organizing files.