My beloved T420's bezels are coming apart at the hinge. This has already happened once---I glued the plastic back together---but now is a very inconvenient time for it to happen again. So I'm thinking of upgrading.
For me, the most important factors are:
Portability - I have to carry my laptop with me on a nearly daily basis.
Linux support.
A good keyboard, preferably without the numpad.
An HDMI port.
Good battery life (~5 hours with active use should be plenty but more is welcome).
I'm thinking of going with the 8th generation X1 carbon but I'd like to hear your opinion.
first off, the bezel is like $10 wherever you are, so if that's the only reason to upgrade that's easily fixed. if it's just a final push, then look no further than T480/T490/T495/T14, whichever you can get the cheapest. excellent linux support (spotty fingerprint support though; shouldn't use that anyway), infinitely ugradeable and repairable and absolute stellar performance compared to what you got. make sure you get a good, original battery as aftermarket ones are hit/miss.
I made the same upgrade years ago. skip the carbons and the S-suffix models as they're only marginally slimmer but way more limited in terms of upgrade and repair.
The T14/P14s is so flimsy in build quality that I would skip the entire line. I would rather go through the annoying repair process to replace the keyboard on a T14s than actually own a T14 which flexes in your lap and in your hands.
X13/T14s are actually decent options due to choice of material. They’re hard to find because you have to find a configuration with a good display and 32GB. I still love my T480 though. I just can’t see why they chose such a light build with plastic to appeal to anyone besides their business customers.
Another T420 could be a good choice. They are fairly easy to find cheap and they are the last generation with the 7 row keyboard and non-chipped battery, iirc.
They are not cheap and the 7 row keyboard is quite overrated. Literally any second hand computer for the same price would outperform it in every metric. You also have the problem of choosing between a 13 year old battery or a 3rd party battery.
I've been fine with 3rd party batteries, especially without the auth chip of later models. I used an x220 til it finally gave up recently, and currently use a t520 and a t530. I do prefer the 7 row keyboard though it's not a huge deal. Sure, newer laptops are faster but so what? It's extra expenditure for performance that I don't need. When I want more CPU, I use a server or cluster.