Assuming you are backing up to the same place every night the way you are doing it offers the most protection in case something goes wrong with your main drive. However, for error recovery purposes it might be too frequent. By the time you notice that something is missing or corrupted you may have backed up over the original. Currently, I back up once a week, and before system updates, but I am waiting for Time Machine.I've got Super Duper setup to do a Smart Update every night at 12 AM. Is this overkill?