Just to add to John's 'Save As' tip,
- I often bounce to new tracks which I route directly to the interface. I end up with 3 or 4 working versions of a track that I can A/B using the Exclusive Solo feature.
- After each Mix-Down bounce, I do 'Save As'
- or (if I forget or don't expect to need a backup) use the Auto Save feature under Preferences > File > Advanced > Enable Versioning of Project.
- Then, if I realize I need a back up, I zip into the folder and re-name one of my Auto Backed up files. Then it won't get deleted.
** Auto Save feature is only useful when the projects are small (not tons of Midi or Audio Snap to explode the project size).