According to Adam Engst, Friday the 13th is International Verify Your Backups Day. Every Friday the 13th, you should check to make sure your backups actually work. Obviously, backups are pretty useless if you can't restore from them when you need to. This has actually happened to me in the past, and it's a pants-darkening moment. I've also attempted to verify a backup only to find that it had become corrupted. Catching it ahead of time let me rebuild the backup before an emergency arose.
What's that? You don't back up your computer? Hmm, that's a risky gamble. I'd wager that you probably have something valuable on there. Photos? Music? Bookmarks? At the very least, you've probably got everything set up the way you like. 'Twould be a shame if anything were to happen to that.
There are a few different backup strategies, but I prefer to have one local incremental and one remote backup. For my local backup, I use Apple's Time Machine because it provides constant, incremental backups. That means it keeps past versions of files so that I can restore to the most recent version or last week's version of the file. I back up to a network drive so I don't have to plug anything in to my laptop. I'm told that there is something similar on Windows.
For a remote backup, I prefer Backblaze. It costs $5 per month per computer, and you get unlimited cloud backup space. It backs up constantly, so the only painfully long backup you have to sit through it the first one. You can download current or past versions of your files from their site or their mobile app. I once experienced a SNAFU that left my laptop completely inaccessible and had to download the entire hard drive from Backblaze, and it was actually quite easy.
You may additionally want to make a bootable copy of your computer. This allows you to easily swap out your broken hard drive for the backup. You'll be up and running again in no time. On the Mac, I recommend SuperDuper! For Windows, Macrium Reflect is a good choice. Both of these will allow you to automate the cloning process. These applications will make a 1 to 1 duplicate of your hard drive, so your backup drive should ideally be the same size as your main hard drive.
So that's that. Go make sure you have backups and that they work.
What's that? You do back up your computer and I just misheard you? Ah, very good. Carry on.