[davidmanze]

No, you do not need a 4K monitor. You can judge image colour and contrast just as well on a 1080P monitor.

And resolution?

      Many now are shooting 4K resolution video with the likes of the GH4 and Sony's 4K, so how would you benefit from 4K movies if you cannot use the resolution that they provide? 

 4K is equal to approximately 8MPs, a lot better than the 2 MPs of  Full HD, which is not a lot compared to modern day sensors, many computer monitors are now 4K but expensive, I checked out the base prices of UHD televisions and they are now costing around 500 euros as against 300 euros for a 1080 HD set.

   As we don't seem here to baulk at defending lenses that often can hit the three grand mark, I cannot see that a couple of hundred extra would be anything other than money extremely well spent.

  I soo soo remember in my distant youth when adults around me were saying what a waste of time 625 line television was and how 405 line was plenty good enough for anybody!