Linux

Anything with either the Xfce or LXQt desktop environment would be good enough for you. I heard those are pretty lightweight.

LXDE is kinda nice too.

I'm a big fan of Debian stable for school / work laptops. Older packages aren't great, but if you aren't someone who needs the newest libreoffice version or something, it works fine. Updates will basically never break it apart from major releases (which you have a few years before you have to worry about, although you can upgrade sooner).

If you need to ask for a distro the answer is Mint, if you didn't need to ask the answer might be different, but then you wouldn't be asking.

First you need to explain what you want by lightweight. RAM, Disk, GPU, Pre installed packages? Features?

In beta stage yet, but Cosmic might become the most stable in a few years. I've never seen an open source general purpose Linux DE with that level of seriousness from a business company.

Arch is you know how to use Arch. If lazy then something like Bhodi or Q4OS. I put the latter on a couple of friend's laptops who recently jumped from Windows. Since it is very Windows-like but it uses less than 400mb of RAM to run on a cold boot.

Personally, I run OpenSUSE Tumbleweed on similar hardware.

Not a popular idea but I've been using chrome os flex and it has been awesome.

I run LMDE 6 on my Thinkpad. Takes a bit of initial TLC to get tuned, but it's rock stable.

Cinnamon is a really stable DE, I've had almost zero issues ever with it. It's a little plain, but not ugly, and you can add themes if you really want to pretty it up.

I run PopOS on my T450s. Runs like a dream, but probably not considered 'lightweight .

I have LMDE on my T580.

Debian or OpenSUSE. Can't go wrong.

Mint. LMDE.

All of them would be fine, also what wireless card and does yours have a gpu. Iirc the 580 had an option for an mx150 so I wouldn't be surprised if the 480 had one.

Intel wireless cards are well supported, others not so much

ITT: Every distro

Mint works well on my Thinkpads

You can't go wrong with Debian or Fedora.

Kubuntu works well on mine. A friend has Lubuntu on his.

If you got a Nvidia dGPU I recommend PopOS. It gave me the best energy options and ability to switch between iGPU and dGPU out of the box. It even found new firmware for my T480 and installed it without a hitch.

I use Linux Mint and currently Fedora on my Thinkpad.

I have been using a t450 for the past 5 years as my only pc. For about 4 years I used Arch without any major issues, but my “optimizations” became too much to maintan. For the past year I’ve been using Kinoite and it’s brilliant.

Everything runs good enough out of the box and in my daily use I haven’t noticed that I’m running a 9 year old machine. I even play games that should have no business running on that crusty old thing. Also, the stability is divine.

I have a T560 and i run debian with sway. It serves the dual purpose of getting me more comfortable in the terminal (i even use power shell on my windowa desk top a lot more now), and it runs much better than KDE or gnome did. Im missing some obvious quality of life settings like easily adjusting the power settings (it never sleeps, just turns off the screen and locks). But again, im trying to get more comfortable using the terminal so for me its more of a "take the training wheels off" thing.

Last time I was looking for lightweight distros, I found antix & MX. Both are nice, lightweight debian daughters.

That was over 10 years ago. Still inclined to use them for distros to give to people wanting to exit Windows, though all the voices for Mint make me want to check it out, too.

I have a similar ThinkPad, I run Mint with LxQt, though xfce is a good option too

Ubuntu Budgie

SLACKWARE!!!!

You can run any distro you like on it , but peppermint is is my favourite. Everything you need and nothing you don't.

Will echo the recommendations of debian or mint. I have mint on my 13 year old rog laptop, it's my lab computer and runs klipper for one of my printers, pretty much always up, very rarely reboots. Debian is what I run on my 4 year old zenbook s, pretty much perfect for my uses, it's what I cart around for light/mobile work and I swear it actually has better battery life than it did running windows.

mint is nice but fedora KDE runs also pretty well on my thinkpad x1 yoga gen3

I think what matters most in your case is the desktop environment, not the distro. I would suggest something lightweight and fast such as Xfce with the distribution of your choice. Gnome and KDE tend to use (a lot) more resources than Xfce. I personally use Debian stable with Xfce on all my machines (which includes a Thinkpad x220), but the Xfce default settings are not ideal on Debian so you will need to fiddle with them (it can all be done easily with the GUI, but it isn't the most user friendly experience at first). If you want something that looks good outside the box that resembles Windows I would suggest Linux Mint Xfce Edition, very straightforward and easy to use with good looking defaults !

Mint is always a good point to start when in doubt. Ubuntu is also solid and has lots of documents online.

Any distro should be fairly stable and supported on an older Thinkpad.

I’m currently using Debian stable on my X220 and it’s rock solid.

I agree with other users recommending Mint