How do I backup my email so that I can import it all back in at a later time if I need to?

[Rashkae]

NoOp wrote:

> 
> Mail & News will contain the bulk of a folder, so I've found that it's
> just as easier (and wiser) to just backup the whole thing. That way if
> you need to restore, all of your profiles settings, extensions/add-ons,
> etc., are restored as well. Plus, if you only want to just put back the
> mail bits, you can easily just pull that folder from the backup and plug
> it in.
> 

This.

also worth noting that the OP's original question was to transfer
Thunderbird from one machine/os to the other (unless I got my threads
crossed again.), in which case, backing up it's whole directory is the
way to go.  Your Spam/Ham file (I forget what file it is) is itself
probably one of the most important files to backup besides your actual
mail/address book, but so easy to overlook.