I recently heard that a big part in successful/quick debugging and easing the process of programming is to use a big screen.

I may be purchasing a new computer in the future and this has me wondering:

1)Is the aforementioned statement actually true or is it a bit of a stretch?

2)Have you noticed that this plays a significant enough part to buy a bigger screen if the bigger screen is significantly more expensive?

3)Is it common for developers to work on 13'' laptop screen as their main (and only) workstation (this is what I currently develop on) or is this actually disadvantageous?

This may be subjective but any professional opinions/experiences would be greatly appreciated!