I've always had my readers in a case. Always. And yet, one of them broke in 2019. While being in its case, sitting in my bag. I tripped and fell that day and even though I did not remember to have fallen onto my bag, the reader had a broken display. It was a 7.8" display, I guess they are a bit more fragile to start with. Furtehermore the cover was a slim style cover. Prior to this I'd always had the sturdier kind of covers or a leather case made by Oberon or Noreve.
I continued to use those slim style covers for the last six years, because now my reader doesn't get much out and about time anymore. Which is why I bought one of the clear jelly back covers. The KLC has a full cover sitting in a drawer, too, to use when we have to go to the dentist or some such, but for home use, clear jelly back it is. I wanna see those pretty book covers