Good question. BenQ has this to say regarding LCD monitors:
"In principle, BenQ monitors are mainly designed
for normal use in general customer usage scenarios, and no restriction
is imposed on a monitor running 24 hours a day. However, the lifespan of a panel is around 30,000 hours in the best possible scenario.
A practical assumption would be around 20,000 hours. 20,000 hours equals 2.2 years of non-stop operation, yet the stress put
on all the other components can make this period even shorter.
If you do decide to use the monitor on a 24-hour-a-day basis, please
make sure the entire display is refreshed every 10 minutes and no static
image remains. Approaches include using a screensaver, putting the monitor in standby
mode, or running a completely different wallpaper or background. This is to avoid image retention, which is a technical limitation of
LCD monitors.
Of course, if you need the monitor to run longer on a
24-hours-a-day basis, to find the product is advertised that they are
industrial grade 24/7 could be a better choice."