Nothing seems hard until you do it.

I agree. GP comment brings to mind the infamous reply to Dropbox Show HN which compared it to something users could trivially implement using basic Unix commands.

I wrote my own backup software. Does that count? :-)

That's a lame backup frequency though. One year of data is significant loss.

I add files to the new drive throughout the year. I keep the drive unplugged most of the time but periodically plug it in to add files. I still have a >1 year recovery point in case of fire, but less than that for more mundane data loss scenarios (accidental deletion, etc).

I have more than one backup drive, and rotate them. I just protect myself against aging drive failure by rotating in a new one once in a while.