While I can handle the keep the inbox of general regular email empty pretty well by putting messages into folders that are filed and done or into waiting for or do later mailboxes where I seem to get totally bogged down is my large number of e-mail lists and the mail they create.
I subscribe to many e-mail lists, some are work related (grazing management, sheep management, fiber work, lists for board of directors I am on etc.) some are hobbies (scrapbooking and knitting) and some are general info or chat lists. I have mail rules set so all new messages go into the appropriate lists' mailbox My "regular" e-mail runs to about 150 messages a day and I am managing to keep the inbox to zero at the end of the day, the do later mailbox is hovering at about 30 messages while my waiting for mailbox is about 5 or 10 at most.
My list mail runs to somewhere between 300-500 messages per day depending on the season. I only read/process messages for a list when I have time to handle the replies I know I will need to do. So a particular mailbox may have open, unread messages in it for a while if it's a list I know I will be needing to respond to and I don't have time right now. I also defer reading lists when I am swamped with work and can't get to them, my hobby and chat lists fall into this category.
Where I run into problems is the archiving of messages from those lists. Some threads are useful forever. On some lists I send similar messages over and over so it's helpful to pull up a past message, tailor to the new question and send it off. On others the threads are useful for a while but eventually they lose their usefulness. I've been leaving the various messages in the mailbox for the list and over time it builds up quite a set of messages, some are clearly still useful, some may have value for me as I do my personal scrapbooks (what was I thinking/doing on a particular date) and some are junk. Some were valuable while the debate and discussion was going on but are now not so important.
Historically I've had many mailboxes with the various categories of messages for my regular e-mail (slowly combining into a few larger mailboxes of related items) and one each for my lists. I currently use Eudora on the Mac. I hate all web mail apps I've seen and refuse to use them so solutions that include gmail or yahoo are not appropriate. I am not at all comfortable depending on an ISP to contain my message archive. I'm looking at moving to a new mail client, either Apple Mail or Odysseus, since Eudora has been orphaned and my mailboxes are larger than those systems are used to dealing with. A typical list mailbox for me has between 15,000 and 25,000 messages.
I see 2 problems:
1) How do I prune the list archive when a particular thread is no longer active and I don't need to keep it for reference? The time line of when this happens varies, for some lists it may be days others may be months so date based systems don't work. I tend to forget to go back and delete no longer needed messages once a thread has died.
2)How do I archive huge reference message sets in current mail apps? Have I missed one I should look at? (I have already looked at and rejected Thunderbird) One reason I've stuck with Eudora is the robust mail handling, lots of separate folders and clean and fast searching. Neither currently identified possible replacement is as robust in that area and it's frustrating to try to adapt to a new mail app just because my favorite is being orphaned.
Thanks for any help and suggestions