I'm sitting in front of a 27" 4k screen right now (approx. 160 dpi), at a distance of around 50 cm. Personally I find this absolutely sufficient as everything i

I'm sitting in front of a 27" 4k screen right now (approx. 160 dpi), at a distance of around 50 cm. Personally I find this absolutely sufficient as everything is very crisp. I also have a 16" Retina OLED screen that I use, and while it's arguably much better than my monitor it's mostly due to the higher refresh rate and better contrast, and less the higher resolution, which is mostly imperceptible to me. So I'd say 120-180 dpi is sufficient and pleasant, but individual preferences can vary. I'm not that young anymore so I use a bit larger fonts and display scaling factor already. I have some younger colleagues that look at 8px fonts on their 4k display, which would just kill my eyes. I guess for them it makes sense to have higher dpi.