• Use Gmail Offline and Enable Email Scheduling & Snoozing


Even in today’s connected world, there will be times when you find yourself stuck offline. But there’s no need to panic in these situations; you can still read, search, and reply to your Gmail messages without an internet connection, thanks to the official Gmail Offline Chrome app.
Installing is simply a matter of heading on over to the Gmail Offline page in the Chrome web store and adding this extension to the Chrome browser.
To use the program, open a new Chrome tab and select ‘Apps’ from the top left corner. Gmail Offline should appear alongside other Chrome applications.
This first time you load up Gmail Offline, you’ll be asked whether you want to allow your mail to be saved on the current computer. Remember, don’t enable it on public or shared machines.
Once you agree, Gmail will open (notice how the interface looks different from the regular web version) and messages from the last seven days - along with those in the starred and drafts folders - will start syncing. You can increase the synchronization timeframe to include messages up to one month old by adjusting the settings.
Being offline means that you’re not going to be able to reply to messages, obviously; instead, anything you've written will sit in your outbox and be delivered as soon as you’re back online. Additionally, offline actions such as deleting and moving messages will also take place once you’re reconnected.

Scheduling & Snoozing Messages

Another excellent Gmail add-on that comes in the form of a Chrome, Firefox, Safari, and Opera extension isBoomerang for Gmail. Extremely helpful for power users, the add-on can perform several functions -- the most notable being the ability to send messages at scheduled times and postpone incoming emails.
Additionally, Boomerang lets you throw messages out of your inbox and have them return at a later date (hence the app’s name). The feature is useful as a reminder for bills or event invitation emails that you don’t want to forget about. Yes, you are able "star" anything important, but you're liable to forget them when the due date is far off.
Boomerang can even identify dates in an email and suggest a time when it should be brought back to the top of the inbox. You can also boomerang sent messages, allowing you to follow them up at a later date.
Along with its response tracking, recurring messages, and read receipts, Boomerang is an excellent extra that improves the Gmail experience. While the app is free, you will need to subscribe if you want to remove the 10 messages per month limit.