Data backup principles

Within the IT industry we have an expression that goes something like this:

There are people that take backups, and there are people who have not yet had a catastrophic hard drive failure

I don't trust "the cloud" nor any app that keeps things. How do you know when it will get lost or corrupted or not updated or the supplier go bust? Microsoft has infected files with viruses, Dropbox has been hacked twice, banks lose data - nothing is secure ... unless you secure it yourself.

Principle: if you personally do not have a copy of the data being stored on something, then you do not have a copy of that data.