I am in layout mode, have inserted legend and sundry other items, now I want to save this so I don't have to regenerated this every time I return to layout mode
A common practice is to set-up a template MXD (File->SaveAs) and use this to load layers in.
If on a network share with multiple users, I would put this template into a read-only folder so no one deletes or saves over and bloats the MXD.
You can also add this MXD to your default templates folder. arcgis desktop - Change default "My template" directory for Arcmap layout view? - Geographic Informa...