Thanks, Ben!
I can’t bring myself to create copies as suggested, it’s really messy and in some cases just won’t work. For instance, editing a particle system being used on a character or weapon, editing the copy won’t have an immediately preview-able effect without reassigning, recompiling, etc.
In addition to the old quit Rocket without saving trick, I also version using perforce and submit religiously, so I generally have a version that’s no older than a day to revert to as well. But, that’s really for emergencies.