Fair question.

While I like Backblaze due to their published reliability reports, willingness to accept uploads and provide downloads on HD, and their pricing, I would label them (and Carbonite) as second tier. I know less about Carbonite than Backblaze, so let me focus on BB. I have two main issues with them (and yes, I know lots of members use them). First and foremost is their lack of geographic distribution. Major providers, such as Amazon, keep 3-5 copies of your data at widely separate locations to mitigate a local disaster (such as the data center burning down) - your working copy is at the site geographically closest to you to minimize latency, and it is then mirrored to other sites across the country for geographic redundancy.

According to BB: “Accounts in our US-West region will store data in both Sacramento and Phoenix data centers. Accounts in our EU-Central region will store data in the Amsterdam datacenter.” Anything stored in CA better be backed up somewhere else, because if you were going to pick one area of the US subject to natural disasters (with the possible exception of FLA or the Gulf Coast in Hurricane season), it would be CA, so at least they have a second site. Now the east coast storage in the Netherlands would be an issue for two reasons. First, any data accessed to The Netherlands is going to be sent received via transAtlantic cable (maybe) or Satellite, and the latency is going to kill your performance. Remember, this is TCP/IP, so the packets have to be acknowledged. Secondly, there is no second site listed at all for the east coast, so no geographic redundancy. And I haven’t even touched on the potential laws and regulations that might affect your data in the Netherlands. For contrast, my data on Amazon S3 has a primary storage in VA, less than 300 miles away, and it’s mirrored to secondary sites in the Midwest and west coast. Contrast the latency of a 300 mile round trip hop to the almost 50,000 mile round trip via satellite or 6-8,000 miles via TA cable. That data is traveling about 1 ft/nsec, so you can do the latency calculations. Finally, BB is committed to using consumer rather than enterprise class drives (to save money). That and the smaller number of data centers is why their storage is so inexpensive. I’m sure there is redundancy, but from my experience specializing in enterprise storage for 25+ years for the largest storage companies in the world. That gives me pause, especially with one data center in the east.

I have cursorily researched Carbonite, but haven’t learned more about their data center location(s?) yet, but I’ll post the results when I learn more. Personally, I use Amazon S3 infrequent access (Amazon OWNS the cloud storage market with more market share than the next 4 largest competitors combined), but they do cost more than BB. BTW, according to Carbonate’s site, they host their server storage on Amazon S3 or Google, so they’re just an added cost middleman for that class of storage. They apparently know who has the most reliable cloud storage in the world.

I've been using Carbonite and One Drive for years. Major problem (IMO) with Carbonite - if you accidently delete a file and not realize it, it automatically gets deleted from Carbonite in 30-60 days (depending on plan) - Really? - That's not a very good backup. What's nice about Carbonite - it has versioning, so if you need a prior version of an edited file, it's retrievable. With One Drive, an accidently deleted file can be retrieved years later. Been there, done that. That's a backup. my 2¢

First, I'd consider the messenger(s) of HD failure. You said your CDs / DVDs go back to 2002. That's the age of my various HDs, particularly the smaller sizes that no long have an active / ongoing purpose. Never ever had a problem with any of these, always Western Digital (WD).

What has changed in the nearly 20 intervening years are (a) the way of the CD / DVD drive is going away. Laptops, for the most part, don't have drives anymore. I'd expect the same to occur in desktops. The (b) option of online (cloud) storage is now a consumer-grade option for many, not something of even 10 years ago.

At the minimum, if these image files have value, they should be on redundant storage, including at least one copy on a USB-connected device. What's important is a back-up media that is actively used and regularly confirmed, not in boxes and confirmed every other decade.