I select a Thinkpad with large RAM, large disk storage, high resolution, smallish physical screen, and as close as possible to selecting all-Intel peripheral chips for USB, video, sound, etc. This gives a laptop with huge longevity for minimal upgrade. Also get the largest battery option you can, but that can impact adversely on weight considerations.
Currently still using my ThinkPad T410S which has only had an upgrade to the HDD from 500gig to 2000gig in its nine-year lifetime. And one repair: a keyboard replacement when two arrow-keys stopped working. Though its screen resolution is now starting to feel a bit 'tight'.