There are countless backup suites for Windows, and we certainly wouldn’t advise against using them. But if you don’t have a proper backup system in place, an occasional drag-and-drop copy provides some quick and easy peace of mind.
Naturally, you shouldn’t keep your backups on the same drive as the originals. Consider investing in an external drive: at the time of writing, you can pick up a Crucial X6 1TB portable SSD for £46, or a 1TB Kingston DataTraveler Max USB flash