[BetterRed]

I did not say I never do a 'full Library backup' - I said I have never had to 'restore an entire library'.

Folder and file sync tools (such as Goodsync, rsync etc) can maintain a full copy of a collection (such as a calibre library), without the overhead of copying the entire collection every time. They do a full copy of the collection once, after which they replicate additions, replacements, and deletions to the collection in the copy.

Added: Because I use a folder/file sync tool I can 'backup' ALL my data to USB drives every day, which only takes a few minutes because it only copies what's changed.

BR