I'd say for PPI, I need at least 200+ for reading and typing productivity.
Or lets say double the standard 110, so 220 ppi.
Most websites now cater to high pixel density screens by using 2X images, so they're double the resolution the designer want's the image to be displayed at, then scaled down to fit in the box so they look sharp on high dpi screens. So 2 x 110 sounds about right.
I've just plugged in my 25" Dell WQHD (2560x1440) monitor and attached to to my Macbook to extend the screen.
First time I've used it in since the end of last summer, dear god does it look like crap after using only my 227 ppi Macbook screen and my 326 ppi iPhone all that time.
The thing is - it's a good monitor. It's not crap at all, but in comparison to the two screens I've been using day in and day out I would find it so hard to go back to it now for any text related tasks such as reading and writing. Gaming and video look great, but boy do websites look bad, it's weird.
The smallest 4k monitors I can find are 24", that's 183 ppi. A weird 1.66X increase, I wonder how that would look. I imagine it'll have some weird scaling issues in windows.
If I'm going for 2X then a 27" 5K would be perfect at 217 ppi.
Or if the next jump is up to 8K then 32" isn't bad at 280.
The monitor itself is getting big then though, so I'd probably prefer to have 8K 34" at 260 ppi - but have it curved. You really need it curved once you get to 32"+
I had a 40" flat 4k Philips monitor for a few months and it was awful. Way too big so I sold it.
So, my two ideal next monitors could be either of the following:
- 27" 5k at 217 ppi, with a high refresh rate of 75hz+
- 34" 8k at 260 ppi, curved, with a high refresh rate of 75hz+.