One of my most favourite, handy and reliable apps I've used for years with my Macbooks is #SuperDuper from #ShirtPocket. It's an app that makes a bootable clone of your Mac's hard drive. Not expensive at all and the customer service is A+. Sorry if this seems spammy but it's a non-corporate, no-nonsense and easy-peasy to use #backup app with a very cool Smart Update feature. Since I started with Macs way back when, I've had a few moments when it totally saved my bacon. Recommended.

@dnanian