If you’re using Time Machine as your backup chances are you did a “set it and forget it” and haven’t looked at it since. It would be good to look at it. All you have to do is click on the Time Machine menu and see when the last backup was. It ought to be within the last hour, because Time Machine backs up every hour.
If your Time Machine menu doesn’t show that the latest backup was really recent, maybe you have a bad backup disk (or maybe it’s unplugged). Maybe you never set it up. If you need a new disk, Amazon has a bunch of them that run off of USB power and they are pretty inexpensive. Here’s a link:
You will be very, very happy that you have a recent backup if your Mac’s hard drive goes bad (Wayne, Paige, Randy, me). You can restore your stuff to a new drive, or a new Mac, very gracefully if you have a fresh backup. So be sure you have one.