Thats ridiculous. Two copies is more than enough. Just having one backup puts the odds in your favor of not losing any data.
I've been running a Mac since 1988, and I've never had any data loss. Most of that time was with one backup. I only started using two backups when Time machine was released(only because I like having a bootable backup).
You're experience is not statistically significant. Had you said that you have benn in charge of 1,000 computers then it would be. But one computer is not enough to tel you much.
The rule of thumb is that at all times you should have both of the following conditions
1) Data exist on three difference physical media (a RAID box counts as one)
2) Data should exist at two different geographical locations
The above must be true even during a backup operation
You need THREE copies because the must likely time for a failure is during a backup. A backup stresses the hardware and if it's going to fail that is when it could fail. Then with an incomplete backup you have zero redundancy. Having three copies means you still have a backup even after a failure
The main threat to the data is not a failed disk drive. It is
1) Silent file corruption caused by software or operator error. What happens is a file gets deleted or damaged then you do a backup and in the process over write the only good early copy of the file with the later damaged version. You will not know this happened until later. You need a versioning backup system to address this. Time Machine works for this as do several of the on-line backup companies. Any backup system that overwrites the old data with the current version will not address this problem.
All that said if this is all just a hobby theft's no big deal, do what you like if this is simply for personal entertainment. But ig you have client's data and you professional reputation and ability to earn a living depends on this data then you might go past the minimum and keep fur copies at three locations
I do this:
1) original on-line copy of data
2) on-line Time Machine makes hourly versioned backups
3) On-line backup service keeps automatically up to date, date is continuously sent.
4) I have a fire safe with disk drives that hold copies of my data
A while back I was looking at some 100+ year old photos I got from my grandmother, years ago. I bet that in 100 years there will be VERY few 100 year old photos because almost no one keeps backups properly. It is VERY hard to design a system that will keep data for 100 years. OK I might be wrong if people move data to the cloud, their it is managed by professionals.
