Anything >= 1995 is enough for word processing offline. Maybe even anything 10 years older. The big problem here is that laptops from that era have clumsy screens and are loud as a jet. Battery life might be a problem too.
The real problem is exchanging data with the rest of the world. My old backup laptop from 2006 (Core Duo 2 7xxx) is probably still OK to browse with an adblocker. I'm not sure it would be OK to edit on a site with a SPA frontend (Medium, etc.)
My current laptop is from 2014 (i7 4xxx) and it's still perfectly OK to do anything I care about. It was never OK to do other stuff (e.g.: gaming or ML, which was not a thing back then.) Of course it's slower than more modern hardware but not by so much for what I have to do () Certainly not for browsing or word processing.
() It's slower than my customer's M1 on Rails test suites (5 s vs 8 s on a project and 50 s vs 75 s on another one). To be fair, my customer is handicapped by running docker on his Mac but docker and the M1 are their choices.
The real problem is exchanging data with the rest of the world. My old backup laptop from 2006 (Core Duo 2 7xxx) is probably still OK to browse with an adblocker. I'm not sure it would be OK to edit on a site with a SPA frontend (Medium, etc.)
My current laptop is from 2014 (i7 4xxx) and it's still perfectly OK to do anything I care about. It was never OK to do other stuff (e.g.: gaming or ML, which was not a thing back then.) Of course it's slower than more modern hardware but not by so much for what I have to do () Certainly not for browsing or word processing.
() It's slower than my customer's M1 on Rails test suites (5 s vs 8 s on a project and 50 s vs 75 s on another one). To be fair, my customer is handicapped by running docker on his Mac but docker and the M1 are their choices.