Answer is to set an auto-rule to archive unread e-mails that are older than x-days. 

 That’s not a half bad idea… 

 The solution is ditch the iPhone  

 And also filter with key words. That one’s a little more tricky, but if you monitor it and adjust it over time, it works like a charrrrrm. 

 I use my inbox as a to-do list / task manager and am religious with unsubscribing etc.