miauu's Set Grid Spacing
With Set Grid Spacing you can quickly set the spacing of the grid in 3ds max.
Just download the script, edit the predefined values(change, add new, delete what is not needed) and installs it.
Autodesk® 3ds Max® and 3ds Max Design® 2009 and above
How to install:
Run the .mcr/.ms script, or drag and drop it onto your 3ds max viewport. Go to Customize - Customize User Interface, and you will find the script in category "miauu".