I noticed that we have a lot of "duplicate" accounts in our Bugzilla DB. Did you know that we can merge your old account with your new one? That means the entire history of your old account will be linked with the new one, so that we can remove the old one later.
I totally forgot this part...
It seems many users don't even know that they can simply change their login name/mail address in Bugzilla. Simply change your mail address in the Account tab of your Bugzilla Preferences. So there is no need to create a new account just because you have/want a new mail address for it. :)