Projects can get really big quickly and with so many different objects it can be difficult and frustrating to keep track of which objects have NoSave and which don't. Moreover, in some cases the ones that need to be saved are only a selected few.
My most recent case is with creating an Undo/Redo feature for a level editor where I only want to save one family of objects. So instead of referencing a single family to save I need to go through hundreds of other objects to add NoSave to.
Save plugin (the polar opposite of NoSave plugin). Objects are not saved by default and need to have this plugin enabled in order to save using Save/Load actions.
There can be an option in Project Properties or whatever with a dropdown "Default save behavior" and options "Save all" and "Save selected".