I have been involved with computers from the days of 20MB drives in the early 80's through to my present 2TB drives. I have never partitioned a drive. If I want to separate one set of data from another I just name them as different files or place them on separate drives. But then I have rarely used automatic backup systems. I tried for a while on a Samsung 1.5TB Storystation but gave up when the backup system malfunctoned. I generally just drag and drop files from my computer drive to external drives every week or so.
If you are worried about hard disc failure then the only secure method of partition is having separate drives.