The display on my previous NDX was always set to come on for the minimum time but started to fade last year, mine was a 2010 model.
The NDS which has replaced it is a 2012 model and that has just had a new display.
It seems that they only last 7-9 years, I’ve been watching the used stock of one particular dealer and almost every item from Unitiqute through to the separates of these sort of ages has been sent back to the factory for a new display before they have been listed for sale.
Apparently the new displays are a different component, hence the need for a trip to Salisbury as it’s not as straightforward as a swap out. Hopefully the new component will last longer.