Using Windows 10 or Mac, to add an expiration date to an email, log in to your Gmail account using your browser, then click “Compose” in the top-left corner of the window.

In the email composition window, enter (1) the recipient’s email address, (2) the subject of the email, and (3) the content of the email.

Next, at the bottom of the composition window, click the lock button that has a clock in front of it. This is the Confidential Mode icon.

Once that’s been clicked, the “Confidential Mode” window will appear. In the “Set Expiration” section, click the down arrow to display a list of different expiration times.

The expiration times range from one day to five years. Select the desired expiration time by clicking it. The expiration date will now appear to the right of the selected time. In addition, you can also require a passcode. Choosing “No SMS Passcode” will let the recipients immediately open the email, while choosing “SMS Passcode” will require the recipient to first enter a password that they’ll receive via SMS text.

You’ll need to enter their phone number if you choose the latter option.  When ready, click “Save.”

The email will now have a set expiration date. A message will appear at the bottom of your email confirming this. Click “Send” to send the email.

If you want to remove access to the email before the set expiration date, click “Sent” in the left-hand pane, then select the message with the expiration date from the list of emails.

At the bottom of the email, click “Remove Access.”  Now, the recipient can no longer access the email.

What Does an Expiration Date Do?

So you’ve added an expiration date to an email. That’s great and all, but what’s the benefit of doing it? Expiration dates are used in a variety of ways by Outlook to help you focus on what’s important. Emails that have expired are generally not as important as emails that haven’t expired, so Outlook automatically formats expired emails differently.

When you open the setting conditional formatting in Outlook, you would have noticed the “Expired items” formatting rule. This rule formats any email that has passed its expiry date with a grey font and the text struck through.

This lets you know that the email has expired so you can focus on more important emails first. If you’ve sent an email with an expiration date, this formatting will be applied in the recipient’s Outlook as well, but other email clients like Thunderbird, or web apps like Gmail or Yahoo! Mail, will ignore the date and do nothing with it.

Select “Date Time fields” from the drop-down and then select the “Expires” option.

Drag and drop the “Expires” item into your folder to add it to the columns.

When you open an expired email, Outlook notifies you with a message in the header.

You can still reply to or forward an expired email, but if you try to forward it, Outlook shows you a warning first.

Click “Yes” to send the email, or “No” to cancel.

Using the Expiration Date to Manage Your Email

Some of Outlook’s built-in tools also make use of expiration dates. If you’ve set up AutoArchiving in Outlook, then you might have noticed an option to “Delete expired items (email folder only).”

If this is switched on, then AutoArchive will delete or move (depending on the other settings) any emails where the date has passed. This is a great way to remove expired emails automatically and stop them cluttering up your mailbox. If you don’t want your expired emails to be deleted or moved, but you don’t want to see them in Outlook either, then you can set Outlook’s synchronization rules to prevent them being downloaded from the Exchange email server.

When you’re building your synchronization filter, click the “Advanced” tab and then the “Field” button.

Select Date/Time fields > Expires from the menu. The field is available in the “All Mail fields” and “All Post fields” options as well.

Set “Condition” to “on or before” and the “Value” to “yesterday,” and then click “Add to List.”

This will filter all expired tasks so that if they expired yesterday or earlier, then they won’t be synchronized with Outlook and won’t appear in your mailbox. They’ll still be available in the Outlook web app if you want to see them there.

You can’t set up rules to add expiration dates to incoming email automatically or create a quick step that applies an expiration date at the press of a button, but you can automatically add an expiration date to all outgoing emails.

Click File > Options > Mail, scroll down to Send Messages and switch on “Mark emails as expired after this many days.”

Enter the number of days after which you want messages to expire and then click “OK.” This will automatically add an expiration date to all of the emails you send.

Expiration dates are a useful way of managing your priorities and your mailbox by low-lighting messages that are no longer relevant and allowing you to use Outlook tools to delete or hide messages you don’t need anymore. It’s one more tool in the fight to prevent your mailbox from getting out of control and a very useful tool at that.

What is AutoArchive in Outlook and how does it work?

If you’ve used the mailbox cleanup tool, (File > Info > Tools) then you’ll have seen the AutoArchive button, but you may be wary of how it works and what it’ll do. Here’s what it does and how you can put it to use.

Clicking the AutoArchive button causes a process to swing through all of the folders in Outlook and apply any AutoArchive rules you’ve set up (don’t worry, the default AutoArchive rule is to do nothing, so you can’t do any harm by clicking the button). But if you want to move your older items to an archive where they’re out of the way, AutoArchive is how you automate the process.

Here’s how it's done!

First, you need to turn on AutoArchive and choose its settings. Go to File > Info > Options > Advanced and then click the “AutoArchive Settings” button.

As long as the “Run AutoArchive every” option is switched off (which is the default), AutoArchive will never run.

Once you turn the “Run AutoArchive every” option on, all of the options are now available.

Unlike Folder Cleanup, which has one window of settings in File Options and then allows you to run those settings against any folder you like as a manual task, the AutoArchive settings shown here are the default settings. Each folder that has AutoArchive switched on can use these default settings, or you can use different settings for different folders if you want. We’ll go through how to do that later on, but for now, let’s look at the default settings.

How To Set Up AutoArchive

The first thing to notice is that once AutoArchive is turned on, it will run every 14 days. You can change that using the Up and Down arrows or by typing a number in, and you can select any value from 1 to 60 days. You can type in any two-digit number, but if it’s more than 60, Outlook will display an error message when you click “OK,” and you’ll have to change the value before you can save.

The next option—“Prompt before AutoArchive runs”—gives you the choice of having Outlook show you a prompt before the AutoArchive happens.

This prompt lets you review the settings or cancel this run of the AutoArchive if you want.

The other settings relate to what items will be archived, and what happens during the archive process. The first option here—“Delete expired items (email folder only)”—relates to emails which have had an expiry date added to them. This won’t affect tasks or events, even if you turn AutoArchive on for those folders.

The rest of the settings apply to all items, not just email. This means calendar events, tasks, notes, and journal entries.

Assuming you leave “Archive or delete old items” switched on, the default settings are for Outlook to move items older than 6 months to a new, separate .pst file named Archive (by default) and make this visible in the navigation pane in Outlook so you can access the archived items whenever you want. You can change the “Clean out items older than” value to anything from 1 day to 60 months, pick a different .pst file to archive the items in, or choose to “Permanently delete old items.”

Be warned that this deletion bypasses the Deleted Items folder, and your items will be deleted from Outlook entirely. You may still be able to access it on your mail server, depending on your settings, but you shouldn’t rely on this. Only choose this option if you want to delete the items forever.

When you click “OK,” AutoArchive will be turned on. It will run in line with the “Run AutoArchive every” value you’ve chosen (every 14 days by default), starting today. So once you turn it on you should expect it to run quite quickly, usually within 15 mins. AutoArchive only runs by default on a few folders, so if you want it to run on specific folders, or you want to customize how it runs on different folders, se below.

How to Turn On and Customize AutoArchive for Different Folders.

When you turn AutoArchive on, it only runs by default against the following folders:

• Sent Items

• Deleted Items

• Calender

• Tasks

If you want it to run on any other folder, you’ll need to turn it on for each folder (or turn it off on any of those four folders against which you don’t want it to run). Do this by right-clicking the folder in the Navigation pane and clicking “Properties.”

You can also access folder properties by selecting Folder > Folder Properties in the ribbon. (For folders like Calendar and Tasks that don’t show up in the Navigation pane, this is the only way to access the folder properties.)

There’s also the option to go straight to the AutoArchive Settings, which saves you a step once you’re inside the Folder Properties.

In the Folder Properties window, click the AutoArchive tab to access the settings for that folder.

For most folders, the “Do not archive items in this folder” setting will be on by default. This means that when the AutoArchive process runs, the folder will be ignored and no items in it will be archived. If you want the folder to be included, switch on the “Archive items in this folder using the default settings” option. Alternatively, if you want the AutoArchive settings for this folder to be different from the defaults, switch on “Archive this folder using these settings” and amend the settings to your preference.

If at any point you want to return all folders to use the default settings, you can go back to File > Options > Advanced > AutoArchive Settings and click the “Apply these settings to all folders now” button. That will change all folders that have the “Archive this folder using these settings” switched on to have “Archive items in this folder using the default settings” switched on instead.

Once yu’ve got the AutoArchive default settings, and the settings per folder, set up the way you want, you can leave the process to quietly work in the background, freeing up space for you and keeping your folders from getting too bloated.