I've only got my e-mail back to 2007. There was a crash at that time and I lost my website and e-mail.
I have several BM mailboxes, there was a purpose to it at one point but really there isn't a distinction between them all these days, except probably the Paypal one.
In each box I have a top-level Read folder where I store all the received messages which I've already read. There aren't really enough messages to need any further sub-division than this.
I clear out my inboxes every couple of months and try to have no more than 2 months' worth of messages in my inbox.
All my sent messages are in the Sent folder in each box, and I don't divide them up any further.
For work, most of our mail comes through a general mailbox which we all can access. It means any one of us can see incoming and outgoing mail without the need for endless forwarding of messages from one desk to the adjacent desk, which is what seems to happen in lots of other businesses.
It does have its problems though, as Thunderbird or the server seems to get a bit confused sometimes with several people being connected to the box at the same time.
The box does get rather unwieldy very quickly, as you might imagine, as there are several hundred incoming and outgoing messages each day so I've devised an enhanced version of my own system above to try to keep it tidy.
We have a separate "archive" mailbox which has year folders from 2008 or whenever I started it, up to 2014, and I put the read incoming messages in those folders when they are finished with, keeping the last two months' worth in the inbox before moving them to the archive 2014 folder.
With outgoing messages I have Sent 2008 up to Sent 2014 folders in the archive box.
Unfortunately Thunderbird seems to have problems bulk-moving messages between different mailboxes. Firstly it does it by copying every message to the destination and then deleting them from the source when it's finished the copy. This means that if the operation breaks down part way through you have loads of duplicated messages in the destination.
If Thunderbird had any brains it would copy-delete, copy-delete so that this doesn't happen.
Also under Windows, trying to do any operation that lasts more than a couple of minutes is utterly hopeless as it times out and insists that you re-enter the mailbox password, and sometimes doesn't even accept the password so the operation ends up being cancelled.
To move messages I have to do it in Ubuntu, which will let Thunderbird stay logged in for hours when moving messages without any timeout problems.
But sometimes it ends up restoring all the moved messages to the source after the operation has finished, which is totally silly, but might be related to having several users logged into the same box.
Yesterday was a case in point, I waited for 3 hours while it moved 1,500 messages from the main inbox to the archive 2014 folder, then I re-started Thunderbird to expunge and tidy up, and it instantly downloaded all 1,500 message back to the inbox whilst keeping copies in the archive box!
If I could stop it doing that then modern life would be good. Ish.