In good old days, people used to receive letters in envelops. During the day, mailman would deliver mail. People would open the envelops, glance at the letters, put the pages back into the envelop and shove it in appropriate box so that they could find the letter again when they really need it. Right?
If you are paying attention then you would say, “Wait a minute!”. You do not collect opened envelops with letters in bins. You take out the letter pages, file them in appropriate folders, take a note of address if needed and throw away the envelop.
Yes, that sounds plausible. But then, why are you saving emails all the time? Emails with spreadsheets from your coworker, emails with photos of an event, meeting or social gathering invite emails and email about other emails are crowding your inbox.
Does your email client allow you to easily save attachments? Does your setup make it impossible for you to create a calendar event from email invites?
If your email inbox feels like overstuffed stomach after thanks giving dinner then why do you keep stuffing it more everyday? How many emails did you read and leave them in the inbox today morning?