It would be useful if Photoshop was able to include separate guide layers ( and potentially be able to change the colour of the each guide (layer).
There are frequently times when there are "master guides" in a document, but one wishes to quickly add extra guides for a specific area of the composition. Currently, these extra temporary guides must manually be dragged off the canvas after completing the sub-task, or a new document needs to be saved before starting to preserve the document with the master guides.