Im using my Asus VW228N for almost 8 years...
Usually the things that start to fail when they are used quite a lot are usually capacitors, the "Things" that deliver the voltage to the rest of components (AC->DC).
Sometimes the LED strip dies, but mostly capacitors.
They are quite cheap to replace tho.
Rarley the motherboard fails of the monitor, but the replacement can be found from china.
Soo it depends on your model.
LCD has pixels which provide color (Liquid crystal),
LED is emmited by led strip (back light), earlier was cathode, which can be found in older TV's from 2010, they are a bit bulky.