I'm looking into getting a new monitor (to go with a larger system update). I'm considering only IPS technology (better image quality than TN and VA, I believe).

A colleague of mine told me he was "hooked" to high refresh rates once he tried one out, and it made a larger impact on him than he expected. It has been long since I last talked to him.

I don't recall ever experiencing a high Hz screen, so perhaps someone with experience can provide their thoughts on the matter. They do raise the price of the unit when we are talking of high resolution screens. Is 75 Hz a noticeable improvement over the usual 60 Hz? I've seen 90 Hz. 144 Hz seems overkill for my uses.

So, what are my uses? Not FPS or competitive gaming. Sure, the occasional first or third perspective 3D game, but also strategy games with little action. But in particular, outside of gaming, do you notice any additional smoothness in desktop use? Say, mouse cursor gliding or webpage scrolling "better"?

Meh. If you're going to go with a higher refresh rate, make it at least 120Hz to be worth bothering with. And it does make a difference, although it has a drawback: once you're used to >120Hz, 60Hz seems slow and stuttery, and not all games can run at 120fps (depending on hardware and settings of course). Yes, that's why Apple and others are moving to 120Hz+ for phones and tablets. No doubt some claim it's just hype, but those people also said that about high-dpi screens, and nobody wants to go back to 72dpi now.

75Hz is noticeable if you are somewhat sensible to motion sickness. I like to use 75Hz over 60Hz for fast paced games, including racing games, even the smoother wheel motion is noticeable.
I use a 27" 144Hz and a vertical 24" 60Hz on main desktop and the mouse movement and webpage scrolling is so much smoother with the high refresh rate. Is so much smoother you almost are able to read text while scrolling ( I use fast webpage scrolling).

Depending on the kind of monitor you want, 144Hz may be the best option, since is more of a "standard" and more units are produced...
My humble recomendation is to get a monitor that supports variable refresh rate (Freesync or G-sync or whatever your computer supports.), it makes playing games that don't support high refresh rates so much easier and there are a LOT of games that don't support 144Hz, including older, "indie" and some fighting games.
Linux Mint seem a little more prone to tearing than Windows and the variable refresh rate helps quite a bit.

IPS and VA are both better than TN, but I wouldn't say they're better than each other. They have their own strengths and weaknesses. The big draw for VA is much better blacks and contrast, which for non-competitive gamers can be a pretty nice benefit. Depends on your priorities. 144hz is amazing, even just on the Windows desktop. Everything is so much smoother and more responsive. In a strategy game like Civ you would feel it very much, because your mouse cursor would be like night and day better. It's especially noticeable in first-person games too, light years more smooth than 60hz. Third-person games are where I notice the benefit the least, but it's still there.

The main problem with 144hz is once you get used to it you love it and hate using 60, but unfortunately you'll have to use 60 sometimes because of very demanding new games or games that break over 60fps.

I went a bit mad one day and brought myself an acer predator curved uwhd ips monitor, up to 175mhz, gsync, about 3*hd, it’s sweeeetttt! Higher refresh works great with fast cards and the gsync works well with nvidia cards. Freesync is a bit cheaper.
So yes, great, but does come at a cost. I managed to convince myself by saying I needed another monitor for my home office so old one was a saving :o)
Oh, and will not be changing it for years now.

Keep in mind that if you want higher refresh rates you are going to need a GPU capable of generating such high numbers.
This become especially true when you factor in resolution: higher resolutions need powerful GPUs, so take a look at benchmarks to be sure that yours is good enough to push high framerates at the target resolution.

IPS is the way to go if you are not in the competitive gaming, LG are selling their new panels to vendors to equip their models with and are better than the last generation.

Panels have a lot of parameters/features, if you don't have special needs then is better to keep it simple.

I recently went from a 60hz monitor to a 144hz one, I was surprised to notice the difference. It really was a smoother experience.

I am on a 1440p, 240 Hz, G-Sync TN monitor and it was absolutely worth it. Upgraded from a 165 Hz at the beginning of this year and it was still a noticeable improvement, especially in FPS games. Not as much as when I went from 60 to 165, but still noticeable. Future proof for years to come too and it is by far the best TN panel I've seen when it comes to image quality (I wrote a review for it here on the forums).

Good luck in the IPS lottery. TN is really not that bad. The main drawback is the gamma shift which is not an issue if you are looking directly at it.

Not only the GPU but all the system has to be capable to deliver 144fps. On most games the CPU have a proportinal increase in load.
Edit: Not everyone need the latest BFGPU on the market to play latest games. A humble nVidia GT710 can deliver enough fps on King's Bounty the Legend or Thief2 to enjoy smooth camera movement.

Also, as a fun fact no one cares about, increasing the refresh rate makes some systems increase idle and low load (browsing, watch movies etc) power consumption, in my case idle power increased ~10W.

it really varies on which games u play because of the developer coding at how well they optimize it, having higher hz is like in drawing more frames in a animations, the higher it is the smoother is it, u also have to count in the size of the monitor and resolution, having a 4k resolution on a 30 something inches isn't great, u'll see like tiny desktop icons, there's also response time though mostly 5ms and fastest r 1ms(i don't know how to truly test this)

1ms is minimum for gaming is it not, if your talking about high refresh times you don’t want slow response times otherwise you may get ghosting.
As for 4K, always found the recommendations to be against it unless you have dual graphic cards very high ones. My 1080ftw runs most things pretty well, and that’s 3k, so it wouldn’t handle higher. Also, how much resolution do you need, they are talking about 8k mostly now, and probably a year or two it will be 16k, it’s more detail than real life!

is there really much difference?

I mean nvidia offers the set fps option next to offering a variable vsync counter and i belief the combination can help with stabilizing anything. i guess amd and intel offer similar solutions

not to mention that 20 fps as extreme example can look smooth too on 60 hz

If you have any fast-paced games - i.e. action titles or FPS's - this is why you want a fast refresh rate.

Get some G-Sync or Free-Sync with it...and it's even better.

These A-Syncing methods stop the input lag, basically - the game, more or less, keeps up w/ your instead of the you waiting for the monitor to keep up w/ you. Also, stopping graphical tearing is important too - as once you have it, you'll never want to go back. No more broken images, lines for a moment across the screen here & there that makes the picture look off, or any of that type of madness.

I didn't realize how important a high-refresh rate and high framerate was, until I got my G-Sync laptop at 120hz. I heard about it, but scoffed at it and thought it was silly...until I bought my SC15 laptop for $1000 a few years back.

Playing GR: Wildlands at 120fps and even getting hit back to 90fps without feeling a bump - was amazing. Smooth as butter and blew my mind. I only noticed it b/c I was purposely watching the graph and stats, telling me I took a massive hit when tons of stuff was happening on-screen - since some of my friends told me how good the tech is and what it does.

Otherwise, on my other desktop PC - I was having slow-downs, stuttters, input lag, etc - taking hits from 60fps to 40fps, stutters, and whatnot - without G-Sync and without fast-refresh on GR: Wildlands. Had to cap it back to 40fps to get it smooth - and ugh, that wasn't ideal, compared to what my SC15 laptop was doing. It didn't feel as fast, responsive, and as smooth.

Even other games at 120hz - like Yakuza 0 - just feel great and play smooth as butter. It's action-gaming bliss.

Yes - high refresh and A-Syncing methods are the way to go; especially for fast-paced titles and action titles.

I frequently switch between a 60Hz and a 75Hz display. I really have to pay attention to things to notice the difference.

60Hz to 120Hz or 144Hz hits you instantly. I'd say anything that can consistently hold up in the 100fps range on average is nice to have, though not something you can't live without. Mind you, this includes an overall system, otherwise there's no point in having the capability of high refresh rates if your hardware can't take advantage of it. I still cringe when I see 144Hz display laptops paired up with GTX 1050s.

It depends a lot on what kind of games you're playing as well. Playing Stellaris at 144Hz is not going to revolutionize your views on high refresh rate gaming experiences, but anything with dynamic movement like shooters and action-adventures will feel much smoother on a good monitor.