Ask HN: How do you handle your personal mail archive?

I have >25 years of personal mail in various mbox, MailDir, .pst and other formats, collected through the years; more recent stuff is also available on some gmail, fastmail and several other provider accounts.

Looking for email is an exercise in grepping all the mail stores, or looking at them through their respective software or service (Outlook, gmail, ...); It's not something I have to do often, but when I do, it's not easy; and I also don't know how long it will be possible -- mail providers go away and change their terms of service; Outlook from 2007 might stop working and Outlook 2020 might refuse to read old mailboxen.

So, I am looking for a way to create a central, usable, searchable personal mail archive, that I can keep updating and that I know will still be usable in another 25 years.

What's your recommended solution?

mailplier, enkive and other "mail archive" solution focus on legal archiving, but that is not my use case. I want it to be open source (at the very least, open protocol and open data format), and self hosted.

I'm on the path to just dump them all as maildir and index them with notmuch - but perhaps you have a better setup?