As the title says, don't be the fool that ends up losing data because you were too lazy to make proper backups! As always, I highly recommend SyncBack Free for the job, since it's quite powerful for being 100% free.
http://techgage.com/article/using_syncback_to_synchronize_your_windows_folders/
http://techgage.com/article/using_syncback_to_synchronize_your_windows_folders/