Ledger nano s has green OLED film display but not LCD one. The lifetime of green OLED emitters is ranging from
46,000 to 230,000 hours so there is no need to worry about its state if it is powered on a couple of hours per day. The most dangerous for this type of display is a water. That is why you need to do all you can to prevent water (condensate including) from coming inside the plastic case of Ledger nano (both s and X).
This is totally wrong assumptions, it is well known fact that display is weak spot for this devices, and you can find countless reports from people who complained about their screen going dim or totally stopped working.
I know exactly what
cheap display model Ledger Nano S is using and you can purchase it for few bucks online, when it stops working after few years of normal usage (Not talking about device constantly connected to computer).
There are several
video instructions for replacing display yourself, or you can use
smartphone camera to mitigate this issue.
If you want to check my claims just type phrase
ledger nano s display problem in browser search or youtube, and you will see clear results.
In addition to this, keeping your device non-stop connected to your computer can be a security risk.
Just for comparison, I don't know a single case of oldest hardware wallet Trezor One with bad or faulty display going dim.
That doesn't mean it's can't happen like for any other devices, but that is not something happening in mass scale.