SyncBack SE

You might have some folders or maybe even an entire partition dedicated to duplicate files and backups of your most important documents. If that's the case, SyncBack can be really useful for keeping these backups updated. It works in a really simple way: the program syncs the original files and their copies so you always have the latest edits saved.

It can be especially useful if you use several different computers (your work computer, personal laptop, desktop computer, etc.) and want to keep your files synced. SyncBack also has endless customization options, filters, and configuration tools. Best of all, it's completely free.