I have a Sony PRS-T1 and the screen is in good shape (no scratch or anything) but the software (or maybe circuits) doesn't function properly anymore.
Then I had a Likebook Plus and after a year of use I accidentally triggered its fall from a 1 meter tall shelf to the ground, it had a cover but it didn't prevent the damage. The screen looks like new but it just doesn't show an image anymore, it's forever blank. Different technicians told me that the battery and the circuits seem fine and that it must be the screen itself.
After that experience I decided to buy just ereaders with durable screen, so I did a little research and found that those with the "mobius" tech are the most durable because it use a substrate from plastic instead of glass. Sadly only the screens with more than 8" screen use it, Kobo Forma being an exception.
Now I have a Likebook Note and my brother has a Kobo Forma following my recomendation. And I hope the truly flexible screens arrive sooner than later. Good luck.
tl,dr: Look for a Eink reader with "mobius" screen.