I am making a cube whose material is reflective plastic [With Principled Shader], And now I want the background to be checker Texture,So that the cube reflect the texture giving a cool sense, My problem is when I choose the checker texture As a background I didn't know the scale of it to be small ... I tried a very big value and i tried a very small value but the two didn't work,what is the value could i choose to make the background checker texture ? I am using cycles render,blender v2.79
Use a Checkered texture connected to you world background shader, then just provide it with correct texture coordinates.
From a Texture Coordinate node use the Window coordinate output to get a flat 2D-like background.
Adjust the size with the Checker texture Size parameter, and the proportions with a Mapping node.
They should be relative to the Render Output image aspect ratio you have set in the Render Properties tab. For example if rendering at 1920x1080 you would get $1080/1920=0.5625$