My 256GB Air, which is my work+personal computer, shows 94 GB free. That's my whole job, my paperwork, Apple Photos library with 5 years worth of data, all my apps and personal projects, all my ebooks, memes, notes, screenshots, cached music from Spotify, everything is in there.

I do have a 4 TB NAS at home, but that's backups and childhood photos, no daily-driving stuff. I don't consider myself a casual user.

I have a 150GB temp directory on my laptop, and I don't consider myself a power user (no video/audio editing, no modern games, etc.). 256GB is really tiny, even for my mother who just keeps local copies of photos and documents etc.

("temp" like "stuff I occasionally need", not literally /var/tmp)