Put all stuff in your inbox

An inbox is one, single place where all stuff goes to be organized, attended to, or eliminated. No stuff, physical or mental, is stored outside the inbox.

You do not need to know what you are going to do with stuff before placing it in the inbox. In fact, you do not even need to know that the object is stuff. All that is required is a shred of doubt that the object is not reference.

Get an inbox, however large you require, to hold all of your stuff. It can be as small as a desk tray, or as large as a commercial storage locker.