Sketch has the option to add outside gutters to the grid. What are these for and what would be an example of a situation where these are useful?
Answer
If you only have internal gutters, the content might seem cramped within the borders of the sheet or screen. When you add the external gutter, you create some breathing room between content edges and physical edges, making it look like things fit more comfortably.
On borderless media (paper, signage) it also creates some buffer space between the background and the content, reducing optical bleed, and making it easier to focus.
Attribution
Source : Link , Question Author : Ben Suarez , Answer Author : PixelSnader