I just figured that HDDs can fail at any random moment
Anything can fail at any random moment, whether it be HD, SSD, or optical. So I agree with GZ and you should keep multiple backups in multiple formats. That said, I always buy "enterprise class" hard drives because they are designed to be run 24/7/365. (See
Enterprise Class Hard Drives).
Am I the only person who backs up to DVD and stores the DVDs in a safe place? Or is that now ancient practice?
No, but sadly, you appear to be one of the few who actually does backups.
I have several backup strategies. First, all my PCs are configured with a small HD or SSD as the boot drive, and another drive for all my data and program files. So if I loose my boot drive, I still have all my data. Then I have my old XP machine downstairs serving (figuratively and literally) as my backup server/NAS.
Then I also have images burned to DVDs and for my little IT consulting business, I keep a copy of that image in my safe deposit box at the bank.
Off site storage is essential as it ensures you still have access to your data in the event your house is blown away by tornado, burned by fire, flooded, or if you are burglarized and your computers are stolen (sadly, people don't even consider "physical security".
Another thing I do is store all my data somewhere under My Documents. Then all I have to do is drag and drop a copy of My Documents onto the networked computer in the basement and now I have current backup of all my data. And certainly, all my data is worth much more than all my computers.
And then there is on-line storage - like Carbonite. I have not used it because I don't yet fully trust "the cloud" to protect my data from loss, or hackers. But Carbonite does appear to be a good alternative.
Electronics life is measured in Power on Hours...
I wish I knew how POH came to be a measure of electronics. It is not really. Electromechanical devices (like hard drives) maybe. POH came out of
MTBF - "meantime between failures" rates. It is measured in hours, but not "power-on" hours. Although it may not seem logical to consider failures while powered off, that time must still be factored in. Simple aging, environmental, galvanic corrosion due to dissimilar metals in the devices, power surges/anomalies (when powered on) and other factors affect life expectancy. Even the expansion/contraction of the "matter" during heat up and cool down (power on, power off) cycles affects aging (as opposed to running 24/7 at a constant temp).
You cannot leave a brand new electronics device on a shelf for 10 years and have certainty it will fire up.
This is especially true of things with grease in them - like drive and fan motors, and other mechanical, or electromechanical devices. POH with devices with moving parts may help determine reliability, but for pure electronics, it is not a good method of comparison. In fact, if not mistaken, POH came out of, or became commonly used by marketing departments of hard drive manufacturers. Not out of the pure electronics side.
At least with DVDs, I don't have to worry about mechanical failure
Assuming the initial "burn" was a success, this is basically true. But note optical disks are NOT considered good for
long term (years) archiving. They even have a name for it -
Disc Rot and it particularly affects recordable (not factory pressed) disks.
Oh, BTW, speaking of scratches - a rubbing a clean thumb smeared with toothpaste over a scratched disk can "polish" the scratch right out and make the disk usable again - if the scratch did not go all the way through the protective layer. It takes some force and when done right, your thumb will get pretty warm from friction. Then a careful rinse and polish with a clean, lint free microfiber cloth finishes it up. This works great for watch crystals too - though be careful rinsing if not water proof.
I label each disc with the date of the backup so I know what I was working on at that time and can go back to get my data.
