What I prefer is keep changing your password every 1 or 2 months because I have seen some cases of my friends who used the same password on other websites and their DB got leaked then their passwords were open source and they didn't even know about it till I made a search on his email on google.
 
What I found was insane a list of email IDs and passwords on 3rd page of google.
And if you think that you have used you bitcointalk password and email somewhere else then you might get in trouble.
I suggest you use  LastPass it's free and has Chrome extension but i am not sure about mozilla extension.