The only way to keep Inbox clean is to archive e-mails very frequently.

Right now I have 26 messages total (unified Inbox in Postbox) and I start getting nervous…
I like to have only around 10 to 25 e-mails there. There are times that I am down to Zero e-mails in Inbox!
You have to have a setup that makes archiving easy and convenient and almost automatic. You don’t want to archive SPAM and manual review of every e-mail message is the only way to keep your archive clean. Sorry…

Epesi has a built in e-mail client - RoundCube - and it handles multiple mailboxes and works great as E-mail Archiving solution for business e-mails, but what about your personal e-mails? Yes, you can setup a personal Epesi Vault and it will work (great for families too), but there is another solution that I use for years: a portable version of MailStore Home.

“The free email archiving software for home users – permanently archive your personal emails from virtually any source:”

https://www.mailstore.com/en/products/mailstore-home/

Very reliable. I track and archive 3 personal accounts since March of 1997 with MailStore.
Business e-mail I archive on regular basis using Epesi of course.
Here is how to do it: https://epesi.org/overview/emailmanagement