Mozbackup

[Raptor]

I'd like to call your attention to a really handy tool that mostly automates the backing-up and restoring of Mozilla Firefox and Thunderbird profiles (Settings, history, saved E-mail, et cetera)

MozBackup

It is a stand alone program and not an extension (Or "Add-on" as they refer to them nowadays..)

Usage is very easy, see the manual for pretty pictures and a very decent explanation without even having to read, really; Mozbackup manual

It creates .PCV files which are basically just .ZIP files so you can always dig through your back-up and edit it manually. Or put it back manually if the program somehow fails.

[Calum]

Definitely a useful program, I've used it myself before.
Very easy to use and reliable too.