Thunderbird sync time? (reverse quota warning)

[E.B.]

> Try to right-click a folder and click "compact". That
> should trigger an expunge.
> There are additional configuration items under account
> settings. You 
> can make TB expunge on exit, you can turn off local
> cache to make it 
> more "live" a la webmail...
> 
> See more:
> http://kb.mozillazine.org/Deleting_messages_in_IMAP_accounts

Thank you for the link