To those who think inbox-0 is a waste of time, because you can just search for email, so why spend even a second organizing it: what causes you to remember to reply to an email sent to you 3 days ago, which is now the 119th email in your inbox?

I subscribe to inbox-0 because emails in my inbox need attention of some kind. I'm not advocating spending an inordinate amount of time organizing every email with labels and filters. Just "inbox == needs attention, not-inbox == I can safely forget about it".