The ultimate solution
The more levels of backup you implement, the safer your data will be
Building a back-up system isn’t a case of picking one option and ignoring the others. The more processes you have running together, the better, as a greater number of them will need to fail in sequence before you risk losing all of your data.
At a bare minimum we recommend running both a Time Machine backup and some form of remote storage system simultaneously. Our preference for the latter would be an internet-based service such as CrashPlan that runs the whole time your Mac is switched on and connected to the net.
Do it yourself
if you prefer not to pay a subscription you can simulate the effect of the aformentioned services – albeit with less convenience and a little less security – by performing manual backups to a series of external drives that you then store in a different building to your Mac. If you’re a home user, then so long as your employer has no objections the solution could be as simple as storing those drives in your desk drawer at work.
When you have a range of simultaneous backups you can stagger the intervals at which they’re performed, with the more cumbersome options conducted less frequently than the automated systems. So, if you’re using Carbon Copy Cloner to duplicate the contents of your internal storage on an external drive you might only perform this weekly or fortnightly, while running Time Machine and online backup continuously.
It’s easy to become complacent, but it’s imperative you monitor each backup. External drives have a finite life, called the Mean Time Before Failure (MTBF) that acts as a guide to how long is can be expected to run before it develops a fault. Make sure you know what the MTBF is as using the drive for continuous backup will eat into the hours more quickly than occasional use. Calculate how far through the allocation you are and swap it out before you hit the limit, even if it appears to be working properly.