One simple, but extremely useful, feature in InDesign is the ability to customise the colour of individual guides.
By default the Ruler Guides, the guides we pull out from the page rulers at the top and left of the document window, are set to Cyan.
If we go to the Layout menu and select “Ruler Guides...” we can choose from a number of different standard colours or specify our own custom colour.
Whilst this doesn’t change the colour of existing guides any new guides will now inherent the new guide colour.
Taking that a stage further, we can also edit the colour of individual guides. Try right-clicking on an existing guide and you’ll see a contextual menu allowing you to access the same “Ruler Guides...” controls. This will edit the colour of any currently selected guide or guides.
As well as the Margins and Columns we might specify for a page there may also additional considerations that Ruler Guides can be used to annotate such as folds, page centres etc. Using colour coding for different guides can help provide some visual clarity when working with more complex page layouts.
If, like me, you’ve ever been on the receiving end a document with dozens of seemingly random cyan guides you’ll see the benefit of a bit of logical colour coding.