If you've made it this far, you probably remember that, on Day 4, we eviscerated labels and folders and advised you to set fire to your complicated folder structure in favor of the Archive concept. To help Filers break an ingrained bad habit, we needed a black-and-white view of the world, whereby folders are a terrible thing. And certainly, as used by many people, they are. But the world exists in shades of gray, and it turns out that folders and labels are valuable, useful tools, when used properly.

There are two specific cases where using labels and folders will improve your email effectiveness.

• You use the label or folder to add a specific piece of missing context to a series of messages.

  For example, if you're tracking all the purchases you've made on behalf of your company, there's no good way to structure a search to find those messages. Adding a label or copying all those messages to a folder adds unique, non-generic, searchable information about the contents of those messages - information that's not anywhere in the messages themselves.

  The same principle applies to tracking things like feature suggestions, research papers that are relevant to a project, or documents related to a specific property you manage. Before you create a folder, consider whether or not you could already find all of these messages using a search. If so, don't create the folder. You should also ask yourself if multiple folders would apply to this email message. If so, your folder structure is too generic. Don't create the folder.

• You use a certain set of search parameters so frequently that you need one-click access to the results. In this case, your label/folder should really be a Saved Search or a Filter. We'll talk more about how to use Rules and Filters tomorrow.

Note: Using labels and folders as your main system for "finding these messages later" is still a repugnant idea. No more than 10% of your messages (and generally less) should be stored in a label or folder. Labels and folders should augment your search functionality, and never replace it.

Another Note: We recommend always using the "Copy" function in your mail client, rather than the "Move" function when using folders. Why? Because that way, a copy of all your messages are in the All Mail folder for easy retrieval and conversation-grouping.

Today your mission is to assess your label and folder situation.

Final Thoughts

Folders and labels are powerful tools when used to add searchable context to a series of messages. Use them carefully, and beware: Folders are the path to the dark side. Folders lead to not searching. Not searching leads to email hate. Hate leads to suffering.

Now that we've talked about how folders and labels should be used, tomorrow we'll talk about how to automate that process with filters.