In using ArcMAP for cartography, we produce and print maps at different scales and extents. Currently, if I want to create 2 maps at different scales (or extents) for the same area then I need to create 2 MXD with the same layers OR use only one MXD and change the layout scale each time i need a map for a desired scale. While the former forces me to create redundant MXDs, the latter make it difficult to revisit the layout for the previous scale.
This idea has been merged with Multiple Map Layouts in Desktop Layout View.
This is because, in an MXD we have the provision of just 1 data view and a layout view.
Wouldn't it be wonderful if we can have Multiple layout views for a single data view all of which can be stored in a single MXD?