Those last two things (saving and deleting) offer you some opportunities to get control of your inbox, rather than just getting through it. And if you do it strategically, you can do in in a minute, literally.
Each time you clear your inbox, take a minute to set up a filter that handles the saving or deleting of one message.
Here's an example: the online statement from your gas company, an investment account, or your mortgage. If you use Gmail (or another web mail service) you can click:
More actions > Filter messages like these
And then set some rules for handling the message, like storing it for the day you pay bills, permanently storing it (if it's on autopay), or starring it so it's an obvious priority when the next one comes in.
You can do that in 60 seconds.
With some creative use of the filtering rules, you can be amazingly precise in what you do with what message, like highlighting a bill you have to pay, but saving or deleting the company's newsletter, even if they come from the same email address. You can learn some tips and tricks here.
If you get Facebook alerts, you can star responses to things you've posted, save for later other messages and delete the list of birthdays.
If you commit to permanently handling one message each time you read email, in a week you'll notice how much faster you can get through your inbox.