Eh, for me only that often if you include stuff caused by a dumb user (aka me). And even then I always got them back one way or another. Usually from %APPDATA%\

Eh, for me only that often if you include stuff caused by a dumb user (aka me). And even then I always got them back one way or another. Usually from %APPDATA%\Mozilla\Firefox\Profiles\[profile]\sessionstore-backups (thankfully there's usually a recent copy, since I'm on a test version) or last resort from backups.