(From https://paulgraham.com/gfaq.html 2025-09-17)

I was thinking about this statement from pg. Nowadays most of the screens (ymmv) I deal with have more than 400 ppi. To my average eyes there's no resolution difference with a standard paperback.

Is it time to switch? Should I guard serifs behind a resolution check on my website? Maybe gradually introduce them on a sliding scale?

I was talking about books. The resolution of computer screens is much lower.