Do / Defer / delete.
I love inbox zero.
I’ve managed to remain engaged in inbox zero since 2010. I do this by selecting from one of three events when an email arrives.
The email contains something you have to do. Enter your energy meter readings, or hand over your bank details to some distant prince who will gladly pay the you sum of $2M USD to get his fortune out of his war torn country.
The email contains something that will require action in the future. The email is marked as “scheduled” or added to a todo list for future execution. This could include renew car insurance which expires in a few months, or researching how much it would cost to go and find this so called prince who drained your bank account.
The email is useless or contains information that is worthless once consumed. In which case the email is deleted. Junk email is an obvious candidate here. As is all email from anyone offering some flavour of get rich quick scheme.
What you do with something once it you are done doing, is up to you. I’ve working on an idea called email zero.