see when i started viewing youtube (2018-19), i had poor internet connectivity, and naturally started with 1080p, but my stream would stutter, so i started to decrease quality 1080>720>540 and so on), at same time, i started to watch stuff at higher and higher speed (normal is 2.3x for me now), and i realized i was not getting anything more by watching at higher res (i increase it to 360-480 sometimes if there is very small font, but rare), so i naturally grew to watch stuff at 144p, now i have good enough connection to watch maybe smooth 2x 4k (sometimes i get 200 Mbps) all the time, but never feel the need to do it (i have set mpv, yt-dlp, all my other video players, to have default res of 144 (or whatever the lowest they serve))

until last year, i used to watch youtube with "3gpp", they used to serve at 144x192 (so 4x3) at ~7fps, which at the usual speeds i watched, seemed pretty good (audio bitrate was roughly 15-20kbps), and was legitimately sad when they stopped doing that, i could no longer have a 10 min video under 5 MiB (with audio)

I used to maintain an archive of content i liked which was almost exclusively self compressed low bitrate x265, and only recently have started to save 720p-1080p (still plan to compress most to 720p AV1 at reasonable bitrates