I made a mistake like this once, I feel most that are really dogmatic about backups have something like this.
A long time ago I had a hard drive fail that had a bitcoin wallet with about 10 bitcoins in it.
At the time it was worth a hundred USD or so. I tried to fix it myself, ended up failing and throwing the drive out.
Right after that bitcoin started its meteoric climb. Every now and then I check the prices, then I go check that my backups are running, that my restores work, that my offsite backup is setup correctly, that every single one of my devices is backed up.
Having lost quite some Bitcoins myself to different errors, IMO it was a hundred USD lesson. You could have replaced them but chose not to. The value therefore was whatever they would have netted you at the time. Worrying about what could have been will just drive you nuts.
I know, I'm not actually as broken up about it as I make it sound sometimes. It was a mistake, and it could "technically" cost me 10 grand, so it's a nice number to remember when I think about the time I'm spending setting up and testing my backups. (And it's a fantastic story to tell others which can often get them to start using a backup system)
In the end, it may end up being net positive in my life when I save something huge later.
Caring to take good backups and the knowledge/skill of doing so is well worth more than $9K in the long run. Losing months of work is a mental killer.
(What's worse is losing 100+ BTC to Gox. :p)
I have not lost anything really important but I cannot live without at least 3 geographically separated backups of generations of backups for something I don't want to lose.
I lost 18 BTC to MtGox... Bought most of them when the exchange rate was about $500.
I knew there was danger in keeping it on the exchange. I wanted to show my girlfriend who bought one of those BTC how easy it was to transfer them to a local machine, to demonstrate the power of Bitcoin because I was passionate about it and thought it had a chance of changing our corrupt banking system.
She kept putting me off, she thought it was some big procedure and just wanted me to do it. I forgot about it after that for a couple of months... Then MtGox exploded.
:-(
If you're out there, MtGox thief, I worked for that BTC. Karma will get you in the end.
A long time ago I had a hard drive fail that had a bitcoin wallet with about 10 bitcoins in it.
At the time it was worth a hundred USD or so. I tried to fix it myself, ended up failing and throwing the drive out.
Right after that bitcoin started its meteoric climb. Every now and then I check the prices, then I go check that my backups are running, that my restores work, that my offsite backup is setup correctly, that every single one of my devices is backed up.
It was a $9,000 life lesson (as of right now...)