@monsterislandcolonizer @burner They changed the numbers in 2020 or so, so the T480 became the T490 right before it was the T14 or something. That's a rough line where it makes enough sence. The T-480/T580, P72/P73 all share about the same size, pluggable RAM and a standard SSD.
The T series have a hot-swappable battery in the back you can change out. The T490 got rid of the ram slots and soldered one in, IIRC. I think it may have a ram slot you can plug in still. Get one of those with the hottest i7 you can find and it will be a quad core good enough to do usual email, browsing, and stream to a single monitor at least. past that it can kind of middle along but if you want serious work of any kind I wouldn't really recommend it, I ended up getting rid of mine, it would bog down w/ clock issues. T580 is the same as a 480 but it has a 15" screen and a full-size numberpad. These are fine work computers but the screens aren't much to write home about unless you drop extra. Good coffee laptops, at least, since the keyboard is easily replaced (and they certainly need it sometimes. a buddy had to replace his 4x at last count, not sure why. His machine is cursed)
If you're willing to carry the heavy brick machine the P series is basically a T-480/580 with a Xeon, extra plugs, and better performance. 17 inch screens, too. Better cooling, and you don't quite have the tranny price increase of the T-series thinkpads. Add a glass trackpad if you want it to be nice and upscale.
The thing to watch out for was the ports: There was an error from the factory that overwrote the chips so your computer w/ 2 thunderbolt ports will only have one. Sure, in theory it was fixed w/ an update but I've seen a couple of these from OEM windows refurbishers that gave up the ghost in a few months of ownership, meaning the update was never installed. That's unacceptable to me, since you have one port for charging and high-bandwidth in that case, so now you have to get a pass-thru dongle on the road, or run USBA. It's shitty, and the reddit type for a lot of the thinkpads makes them about 20% more than they're worth.