“There are two kinds of tech users in the world: Those who have lost data, and those who are about to lose data.”
I’m paraphrasing a popular idiom here, but I find it to be true nonetheless. If you work with computers, you need a back-up strategy. Computers can be replaced, but the data it stores is one of a kind, whether its personal photos, important documents, creative media etc.
My back-up system is multi-faceted. It involves having both local back-ups and off-site back-ups. Local back-ups make sense: having more than one copy of data on an attached storage device provides peace of mind. But off-site back-ups are equally important. Should the unthinkable happen, and I lose my home due to a fire or natural disaster, I don’t want my data to go with it.
Hardware
For context: I have two Macs, a laptop and an M4 Mac mini with 512GB storage. The MacBook Pro is connected to an OWC ThunderBay 4 enclosure, which is populated with four drives.
I’ll use my Mac mini’s boot drive as an example here, but I apply the same strategy for any attached storage I connect to it. I have a separate 512GB external NVME drive attached to it, which serves as a clone of the internal storage. For every storage device I actively write data to (SOURCE), I have a separate storage device serving as its back-up (CLONE).
The ThunderBay 4 enclosure contains two SOURCE drives, with two corresponding CLONE drives.
My advice when buying new storage is to buy in twos. (Buy once, cry once.)
Software

For cloned back-ups, I use SuperDuper. It has been my go-to for reliable back-ups for more than a decade. SuperDuper lets me set a specific back-up schedule for each SOURCE drive on my system. At the scheduled time, SuperDuper will launch and make back-ups to the CLONE without my intervention. (From time to time, I will check the integrity of the back-up to make sure that my data is intact. No issues thus far.)
macOS includes Time Machine, a software back-up solution. I have assigned a separate drive for Time Machine, set to back-up specific files and folders on my MacBook Pro’s internal drive. Time Machine takes snap-shots of these files / folders, allowing me to “go back in time” to revert a file back to an earlier state. I don’t use this often, but it does come handy in the times I need it.

In addition to cloned back-ups, I also sync specific folders between my two Macs. This allows me to work on the latest files on either of my Macs. Syncing insures that the same files exist in two places, and for that task I use ChronoSync. Like my cloned back-ups, ChronoSync offers scheduled syncs.
The Cloud
For off-site back-ups, I use BackBlaze. There’s a monthly cost ($7US) associated with this, but BackBlaze offers unlimited data back-ups. Should I lose all of my local data, BackBlaze will overnight a drive with all of my data. I hope I never have to take advantage of this, but again – it’s really for my peace of mind.
Final Thoughts
Back-ups are important. New computers can be purchased, but your data can’t. Choose wisely.
-Krishna