In 2005 on a Saturday evening, I lost every bit of digital data I had, in spite of following (and even exceeding) this rule. I had:

- One live copy of data on my laptop

- One copy on external hard disk, updated ~daily, on-site (home)

- One copy on external hard disk, different brand and age, updated ~bi-weekly, off-site (work)

- Immutable copies on optical media, persisted ~once a month, on-site

Data on the laptop was lost due to operational error: I fat-fingered a command and destroyed the partition table and part of the leading data on disk. Being a reasonably fast disk this ate a lot of structurally critical data quickly. Recovering the filesystem would be really hard, but I had a two days old backup, so didn't think much of it.

Now, to the local backup. I booted up a live cd, rebuilt a partition layout, plugged the disk in, and started restoring data. Reboot, and it seemed to work, mostly, but some things that should were not. Immediately jumped to look at the recovered data, it was severely corrupted. Diffed some files and compared to the "originals" (i.e from the backup) and they were identical: data on the backup disk was hopelessly mangled even though the hardware was fine. A cursory analysis seemed to highlight a software bug (filesystem code? drive firmware? whatever, the issue had some logical consistency to it that made it obvious it was unrecoverable, which was my sole goal at this point). And I just restored it over what remained of perfectly valid - if difficultly reachable - data, essentially scrubbing the laptop disk. Sweat was starting to build up.

Okay, optical copies were next, even if older. Surely this would get my heart rate down. I put the disk in, closed the tray, and heard the sound of a rattling helicopter. I stored the disk in a closet which I thought would be safe, but it turns out the hot water pipes for the flat above were running behind a thin wall, which build up enough heat over time inside the closet to slowly warp the disk. Well, one of them, because I was paranoid enough to have three disks for a 3 month rotation; but while the other disks were geometrically fine (maybe due to being a different brand), they were stored for a longer amount of time and their data suffered much bitrot. This was going to be a long Sunday.

Back at work on Monday, the final disk immediately emitted an ominous clicking noise right away. Shortly after it snapped, never to power on again. I could maybe recover data straight from the platters if I sent it to some firm for a hefty pile of cash, which I had none at hand, neither at that time nor in the foreseeable future.

So, in order I experienced: an operational error, a logical error, an environmental issue, and a hardware fault. Luck had it that I had a second computer temporarily lent to me, which I toyed with and where some of my most recent work files turned out to lie from a week before, so I could resume putting food on the table quickly. No amount of hackery was able to restore any meaningful data, so I lost about 10 years of digital photos and older work archives.

Psychologically it was fairly interesting, because I thought I would be enraged at myself for multiple reasons, but the perspective of such ridiculous odds of this happening turned the whole thing into a very contemplative experience shortly after.