Review for Automatic Export by David Busto
Rated 5 out of 5 stars
Great. Does what it says it does.
it really automatises the task of creating a backup of your calendar (and that is the kind of task I usually forget when I format my computer) Works perfectly, I suggest adding a button to the calendar in thunderbird to the end of establishing how often you want to create a backup (12 hours recommended).
To create your own collections, you must have a Mozilla Add-ons account.