I too did exactly this around 5 weeks ago for my personal email address, and maintain an inbox of less than 5 emails at any given time. I spent almost 4 hours

I too did exactly this around 5 weeks ago for my personal email address, and maintain an inbox of less than 5 emails at any given time. I spent almost 4 hours moving old read and unread emails into a small set of folders en masse (thousands of emails). I unsubscribed or set up folder filters for all mailing lists. I went from receiving ~20 emails per day to ~3-4 (in my main inbox). Once you get rid of the nonsense keeping track and archiving the important stuff is really not that hard.