Here's a ppi calculator https://www.sven.de/dpi/ to satify various hypotheticals.

Any 4K monitor 26" or greater is the same dpi as FHD at 13"

Various examples here https://www.newegg.com/p/pl?d=4k+monitor

A 24" 4K monitor is only 8% better in fact. I would venture to guess it would be basically indistinguishable to the naked eye.

QHD at 13" is 226 ppi is that really a reasonable minimum?

It's less about DPI than about raw pixel count. At 1080p, you simply lose too much usable screen space to menus, toolbars, task bars, and all the dumb shit that websites set "position: fixed" on. 2560x1440 (or better yet, 2560x1600) with appropriate magnification gives you a lot more flexibility in how you use screen space, instead of more or less forcing you to work with only one maximized/fullscreen window at a time.

I use a 13" MBP with no UI magnification, but most web pages scaled to around 200%. That keeps the UI nice and compact and leaves a lot of screen space for actual content (about 2170x1523 with my current browser layout). I do occasionally set it to a scaled resolution when someone else has to watch/use the machine as well.

>or better yet, 2560x1600

I couldn't agree more, I was given 16:10 monitors for my current job and I'm not sure if I'll ever go back to 16:9 if I can avoid it. Next laptop is a 13" MBP for sure too.

I don't really get why anyone would use laptop screen or keyboard unless they're traveling. I'm using my laptop purely as a portable computer between home and office desks. I would be quite fine with a laptop without screen or keyboard, at least until someone wants me to present in a live meeting.

I did that for a while, with a Mac Mini.

It was lighter and more powerful than the Macbook Air I've been using the last few years.

(In the end there were times when I wanted an actual laptop with me, i.e. non-work trips away)

Fully agreed, this year is 2020 guys at least provide QHD for laptops and PCs, and have mercy for your eyes.

The only main problem with QHD is that once you've got used to it, it is really hard to go back to anything less.

FHD is not an issue, but there's no mention of whether it's TN or IPS. If it's TN, then it's sad.

what does it change really? If you need more space there's no issue to connect to a real big screen to do more work.

It makes it really uncomfortable to use when you're not connected to a larger screen. If I'm buying a laptop, I want a decent screen for when I'm not sitting at my desk. If I didn't care about that, I wouldn't be buying a laptop in the first place.

So does that mean you did not work on any laptop before 2015 or so when very high resolution screens were basically unavailable?