When we received any Mail We are Storing that E Mail for the Lifetime in our Inbox until we delete. Some Email are not useful after Some Dates & that are not being cleared for mistakenly, Occupying your Inbox Mail Space. What Thunderbird to be done, As we Open any Email on the Taskbar it should Show Pop Up with Two Options, that Till what time or Date you wanted to Save this Email. 1) Do not Wanted to Delete 2) Date & Timer If any one is Set the Date & Time, As he starts Thunderbird, it Automatically Delete on Same Date & time. Hope your had Understood this & In Thunderbird This Will Be Available.