The T and X series Thinkpad are good in my experience. P series seems good too. They're all quite expensive, but I have an X220 I personally bought some time around 2010 that I still use regularly. It's had almost not problems. A year or two ago, the cooling fan broke, and I bought a new cooling system for a reasonable price on eBay. It was fairly easy to replace that. I replaced the hard drive twice because I've had hard drives fail on other computers and I just replace them regularly now. I use the original battery. The life is not as good, but it's still fine. I also have another X220 and a X230 I used for work, and they're still fine but I rarely use them due to some work policies. New hard drives due to the previously mentioned concerns. One keyboard replacement because it was used outside in wet conditions: incredibly easy to replace. These things last a long time. Parts are easy to find because they're popular. Which Thinkpad you'd want is a matter of preference. They come in various sizes and capabilities.

The Thinkpad Edge line, despite the name, is not the same line as Thinkpad. They're a lot cheaper in cost, but they're notably less nice, although still pretty good . They seem like a reasonanle choice if you want to save money. A family member has one where the case and a metal frame broke at the hinge after 8 to 10 years. You'd need to take everything off the case to replace it, so not something I would care to fix, but if one really wanted to fix it one could. It's still fine in other regards. They have a lot of other laptop lines and I don't know them all, but of the other lines that I've used, I'd say they're not worth buying. They're the same sort of cheap construction as other companies.