The T420 is old, but still has some advantages over laptops currently on the market. Up until 2018 many laptops still had dual core cpus like the i7-7500u which are worse than the i7-3840qm that can be put in a T420, and the few currently available laptops that have 1440p displays and quad core cpus are still pretty expensive. Some other reasons people still use the laptop are being able to use coreboot with it and the upgradability of it. It's really cheap to upgrade the laptop to work with bluetooth 5 and wifi 6 and multiple ssd's can be added using the two 2.5" slots and the one msata slot. Using this, someone could make a large 150wh or even 200wh battery that would let this laptop last longer than most new laptops.

The T420 is the last model to feature the traditional ThinkPad keyboard (except for the special 25th anniversary ThinkPad), though it is possible to install the T420 keyboard in a T430. There is still a segment of ThinkPad users who prefer using the traditional keyboard, and some of them are willing to forego the performance and other features of more recent laptops in order to use the traditional keyboard. There is even a market for modded older ThinkPads with newer components, such as the X62 and x210 projects.

I'm running a T530 as my everyday rig, with Windows 10. I maxxed out the ram and got a ssd. It's fast, I can have numerous Chrome tabs, Sublime, and pdfs open, and quickly switch between them. Youtube videos play seamlessly. I can have multiple Kicad projects open. I genuinely don't feel the need for a faster computer.

Excellent support with Linux, the BSDs, and even other obscure operating systems like RedoxOS.

A plethora of repair, replacement, and add-on parts.

A laptop that runs great for an entire decade.

It's got a TrackPoint and is available refurbished now for ~200 dollars.

And yes, the keyboard is very high quality, far above the sorry state of laptop keyboards today.

The keyboard is the appeal; the T420 was the last model with the classic "7-row" keyboard design. The T430 and later have Macbook-style chiclet keys like everything else these days. It's one of the best portable SSH clients you can ask for, so the CPU power of the ThinkPad itself isn't that relevant.

Some people go the opposite route of modding the old keyboard onto newer ThinkPads: http://www.thinkwiki.org/wiki/Install_Classic_Keyboard_on_xx...

I'm still using an X60 which is several years before that. It turns out that if you avoid the bloated "modern" software (which unfortunately includes much of the web stuff these days), it's perfectly usable. I use it for native development, browsing lightweight sites like HN, and the usual "office" stuff like email, IM (IRC), taking notes, etc. Likewise, my desktop is a first-gen i7 from roughly 10 years ago, only slightly newer than that, and also feels more than adequate.

I use an X200, which is the generation before this. It just does what I want for media/web consumption and the light development work I do in my spare time. (I have a more modern Thinkpad for work. I think I'd be able to do the work on the X200, but maybe not in the way that I do with Typescript incremental compiles etc. VSCode would probably also suck.)

The only time I notice performance problems is bad websites, like Twitter or Reddit. But I'm getting a little stubborn about it, TBH, I don't think I should replace a perfectly working computer in order to use a site meant for displaying 500 character messages which worked perfectly well in its old incarnation. (And some of those same sites also suck on new hardware.)

There are a number of things that I do in my day-to-day life which I don't expect to ever change, things like maintaining a journal, sending and receiving text messages via e-mail, IRC or Signal, backup and organize pictures of my family, listening to music from my MP3 collection, watch videos (in reasonable but not ludicrous resolutions for the 12" screen), etc. These are things that I've done on this computer since I got it in 2009, they are completely solved problems and I would be extremely happy to use this machine until I die.

Today, even older 10 years old laptops are quite good at doing usual things like checking emails, browsing the web, watching a video or doing things like that on the go.

Even coding is generally doable (unless your project is extremely massive).

It gets the job done, even if it's not as fast as recent laptop (which is in turn not as fast as a recent desktop).

Also, buying these things can make a lot of sense for some people.

For example, in my case, I'm a big fan of cheap laptop (usually secondhand thinkpad) + decent desktop.

On one hand a decent desktop is much faster than almost any laptops available (and the few laptops that are faster have issues like heat, low battery life and being heavy).

On the other, a small Thinkpad (ex: x250) is a good enough compromise when on the go. Also, as it's quite cheap (if secondhand), so it's not dramatic if it gets damaged which is always more likely for mobile objects. A few years back, I slipped on a patch of ice, felt on my old x61, and completely broke the screen, I just bought another x61 and swapped the disk and it only set me back 130 euros which not as bad as breaking a brand new macbook pro in the same manner for example.

So, yes, in the end, it's worthwhile to maintain them and do things like changing the battery or replacing faulty components. And the after market for this things is quite developed, you can pretty much find any components on ebay or other web sites (I just did it last week with a broken DC jack replacement on an x230). Combine with the fact these are some of the easiest laptops to disassemble, it makes them remarkably serviceable.

Many of the changes to Intel CPU design over the past decade have been related to power efficiency, not necessarily performance. If you don’t care about trying the get every minute on battery, older machines like this are still perfectly usable.

I bought a T420, used, for $200 when I went away to college. I added an SSD to it, making the total around $300.

Six years later, it's still my only personal laptop: it's got all the specs I need[1], and works perfectly with Linux. The only downside to it is finding new batteries; I suppose that's why TFA is building their own ;)

[1]: All I do on it is browse the web, watch videos via MPV, send emails, and program.

I have a refurbushed x230 (12.5'' screen) with a i5 3320M processor, 8 GB ram and an 250 GB SSD. I bought it before a year for around 200 euros. This is the best laptop I've ever owned. It can compete speed-wise with most laptops in the 700-800 euro range and although it has been abused by my 3yo and 1 yo kids (they steps on it, throw it around etc) it doesn't even have a scratch.

It runs Windows 10 and I can easily develop on it using python (big django projects), elixir/phoenix, even java and clojure using VSCode. I think that with some patience it could even be used with Jetbrains editors (Intellij Idea, Android Studio etc). What's even more astonishing is that I can get like 2 hours of medium usage from its 8 yo battery!

What else could anybody want?

After my experience with that laptop I am now in the look for a good deal on a refurbished T4xx (14'' screen).

My current computer is a 2009 MacBook Pro running Ubuntu. Im not poor or anything, it just does what I need- so why spend any money on anything more?

The x10-x30 series are a well known design and perform surprisingly well for 8-10 year old laptops. They're also more maintenance friendly (most T/W series) than their more current models.

You'd be surprised how many people use even older thinkpads. Graphics aside a x41 would still suit my needs. Actually if it wasn't for hd video and fancy css3 I wouldn't need to upgrade until I die. (I avoid scala and eclipse)

Not quite the same model, but I use an X230 (2013 model) as my primary machine at the moment (not counting the company-provided machine I use for work). It’s still a really nice machine, easy to service, and they’re dirt cheap on eBay!