A backup you can actually restore
A few practical habits for personal archives and important documents.
Use a separate device
A second folder on the same drive can be convenient, but it will not help if that drive fails. Keep a backup on a separate device or another suitable storage service.
Know what you are saving
Make a short list of the things you would struggle to replace: documents, photographs and personal projects. Remember the files you rarely open but might need again one day.
Keep more than one version
Version history can take you back to a point before an accidental deletion or an unwanted edit. A single copy that is constantly overwritten cannot offer the same protection.
Try restoring something
Restore a few small files into a temporary folder and open them. A successful copying report matters less than knowing how to recover your own data.