Firefox itself has a built-in feature that automatically backs up all your bookmarks (including Tab Stash's saved tabs), so having such a feature in Tab Stash itself would be redundant. You can find this in Firefox's bookmark manager, where there are options for taking a manual backup and restoring from a manual or automatic backup.
Also, Tab Stash has a deleted-items feature that will keep track of deleted folders/tabs so that if you delete something by mistake, it's easy to recover.
