So… out of hard drive space, and time to clean up…
When I begin to work on a project I copy the camera memory card onto the hard drive, and then go through the Log and transfer process.
When I finish working on a project, but still want to keep it available for further work, it seems like a waste of space to keep both the original card copy, and the capture scratch folder.
You should never keep the camera masters and the imported media on the same hard drive. If you lose that drive, all you media is gone.
When shooting tapeless, you need multiple hard drives. Drives you archive your camera masters to, that you keep and store. Best to have two sets of those drives. Them your media drive that you import the footage to and work from. When done you can trash those files, as you can always reimport. And just archive audio files and still and graphics.
I also choose to archive the media used in the final locked piece. Media manage the footage with handles to yet another drive (cheap ish USB). Because I always reuse my media drive, but often have to revisit old projects.