As I have been using firefox to store relative sensitive informations (like certificates) there is a STRONG recommendation to turn on Master Password. This encrypts and secure the databases for firefox (and thunderbird) so that cookies, passwords and certificates and so is protected. And even of someone can hack into you computer they cant get to that information.
I like that security function, but it has one downside. As I have 8 tabs that i start up with, the password question pops up multiple times (like 2 or 3 times) when I start up the browser.
A bit annoying. And the same goes for thunderbird. There I have to answer the password question 2 times.
But yesterday I did found a add-on (one for firefox and one for thunderbird) that fixes this, as well as giving you more features for master password.
So I installed it, and configure it to ask for password once when I start up and it takes care of it all.