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This is the reason why we should not store our money in one address but rather spread it. That scenario shows us how important is to not just set aside our fund's security but instead, make focus on it and ensure that it is safe at least 99%. Otherwise, we give these hackers easy access to our wallets.
You shouldn't focus on single addresses but rather on wallets. Leave it to your wallet software to manage your wallet's addresses and try as early as possible to use a decent hardware wallet to secure your private keys (forget closed-source Ledger crap).
Software-only wallets are only secure if you have a strict air-gapped setup where the private keys are in the air-gapped cold section and your online hot wallet section is watch-only, i.e. without exposing private keys to an online device.
You need to have redundant secure backups of your wallets. No matter what, period! Storage devices can fail: no backups, no mercy!
If you observe very well in that case that happened for that guy to lose his BTC, you will discovered that the guy is part of this category of people who just heard that if you invest little money on BTC and hodl for long you will achieve huge amount of money without settle down to know how to write the seeds phrase in a secure please for future purpose.
The guy who lost his coins bought and/or mined his Bitcoins back in 2012 and used a BitcoinGUI wallet (there's no more details in the reddit post about this). Back then as far as I remember there were no HD wallets with backup recovery words (don't remember when Armory wallet showed up first). So that family member of the reddit poster used BitcoinGUI (today Bitcoin Core) with a wallet.dat file full of independant random private keys. If you had to backup such a legacy wallet, you had wallet.dat file backups.
Apparently the guy who lost his coins didn't have that. Big and now very costly fault!
Sometimes, things like this happen for other people to learn their lesson so that they will be careful where they store their BTC and, if you use good wallet to store your BTC and you keep the seeds phrase in a safe place, you don't have anything to fear.
It's too expensive for the lesson that they have to learn. They don't treat it as if it's the most important thing that they need to secure and that's why the are too vulnerable while the people that they whom trust sees their vulnerability, they take advantage of them. I even have a laptop have it repaired and even though I have a wallet installed there with not that much, I still check it out and never lose my eyes on the technician and that's what is giving importance to your thing because it's not just about the wallet but also about the parts that you're allowing these techs to fix them.
As soon as your coin's value exceeds a four-figure $$$ you should make some risk assessment of how to prevent certain loss cases. I would use encrypted file systems to mitigate exposing my wallets to device theft. An encrypted file system also prevents exposing your valuable data and wallets to repair technicians.
Show me a repair shop that allows you to never loose your eyes on those who handle your device. Not impossible but somewhat unlikely. If it's not the storage device to repair, you could ask that the first thing they do for the repair job is to extract the storage device and hand it over to you so that a technician wouldn't ever have a look on the device's content.
The first mistake of the guy was trust a device to hold his bitcoin keys there have been warnings of wear of this devices and that’s what happened.
Where do you phantasize "have been warnings of wear of this device" from the quoted reddit post or OP's post? Seriously!
Firstly I see this story mor like fiction and not real, the data recovery specialist must have a knowledge about the whole bitcoin thing and was also aware that the drive brought for repairs has the seed phrase either it was the owner that told him or he cracked the drive and saw the keys. This is the only two scenario because seed phrase on a device doesn’t mean that bitcoin was on that device because bitcoin are stored on the blockchain and only keys stays on the device which means someone has had access to those keys and moved the bitcoin elsewhere.
To my knowledge there were no wallets in 2012 with "seed phrase" or more precisely mnemonic recovery words and the story is about a guy who bought/mined coins in 2012. Don't make assumptions out of nowhere, this doesn't help the topic here.
We simply do NOT know what that guy told the repair technician, nor what was on the corrupted hard drive besides the wallet.dat file. There's simply not enough details exposed in this story and topic by OP.
Was the wallet.dat not secured with a decent wallet passphrase? We don't know.
Was the wallet.dat wallet passphrase in clear-text in a file on the harddrive? We don't know.
Was the wallet.dat wallet not secured at all? We don't know.
Re-reading the reddit posts again, the story seems a bit wacky. Reddit OP speaks first of a corrupted harddrive, then later in the reddit thread it's a thumbdrive. Both are completely different storage technology with their own very different technical issues that could arise.
Nevertheless whatever is true, from every loss story there are lessons to learn from.