Mozilla Thunderbird IMAP quota
Did you know that Mozilla Thunderbird IMAP quota can be displayed at the time at the bottom of Thunderbird's window?
Basically this functionality is built into Thunderbird but the quota is only displayed when IMAP space usage reaches 75% or more.
You can adjust the percentage value by going to about:config (warning, here be dragons) and changing a setting there to a desired percentage. [node:read-more:link]