I have a 22" external monitor hooked up to my 12" laptop and one of the main reasons for this is ergonomics - I put the monitor on a stand, so that the top edge of the screen is at the same height as my eyes, and the laptop's screen doesn't obscure the external monitor's screen.
The end result is that I have a tiny and lightweight laptop for travel and at the same time reasonably big screen for everyday work.
The end result is that I have a tiny and lightweight laptop for travel and at the same time reasonably big screen for everyday work.