Always always always backup your footage. Sure, it's not cut yet, but if anything happens to your footage during the edit or your editing drive breaks or what have you its always important to have multiple copies of your footage.
I work for a post studio and we don't even transcode the raw footage we get in until it is backed up at least once. Twice is preferred but it depends on what the client gives us for backup drives.
You only want to shoot once, and for some stuff you can only shoot once, so don't risk it.
Prime example: last month we had footage come in from a dock one of our clients was shooting. It was about a specific person (I'm not gonna get into the details) and the subject actually passed away during filming (they had footage of him and his funeral). Knowing this we made sure to backup all the footage twice when it came in.
Good thing we did as well because the original drive was accidentally erased by the cameraman afterward and one of the backup drives failed. If we hadn't backed up the footage properly the project would never be getting completed because it is impossible to re-shoot it.
Moral of the story: A couple of $200 hard drives is the best investment you could ever make. Don't risk your footage: back it up.