If you carefully look at the bottom left it tells you.
(Yes this is from a real Inbox 96,118 emails!)
The term INBOX is derived from the office language IN-TRAY.
Would you use your IN-TRAY as your filing cabinet? Hopefully not :)
In essence your IN-TRAY - is your ToDo List waiting for your action.
Why Bother clearing your INBOX?
1. It's good for your software
All of your Emails, Folders, Attachments, Contacts, Calendar and Tasks are stored in one PST or OST file. To keep your Outlook happy and healthy it is important to keep this file from getting too large. Every time you open Outlook the first folder it opens is your INBOX - ensuring this only has a handful of emails in it means it runs faster and can significantly help your email not to lock, crash or at worst corrupt your PST file. (If it gets corrupted the worst case scenario is that you would lose everything)
2. It's good for you
Less clutter helps you feel organised and on top of things.
Keep your Inbox to 30 items or less
Keeping your Inbox as empty as possible can sometimes feel like the hopeless task of sweeping back the sea. It's a discipline and believe me you will feel much better for it - rather like that wonderful 'fresh start' feeling when you make the effort to declutter your space.
If your Inbox is your ToDo List - Ideally you should make your ToDo List achievable - i.e. 10 things to do per day is plently for most people. So 3 days (because you might have had the weekend off) of emails would be a maximum of 30 Items.
Here is a tip I use for paper work which could also be applied to your INBOX. Look at this grid of just 4 actions...
Urgent = High, Important = High
If the email is Urgent and Important (for your role) DO IT – Deal with it right away Then DELETE the email or if you really need it FILE IT in a folder (see If you have Replied Delete It! below)
Urgent = Low, Important = High
If the email is not Urgent but Important (for your role) FILE IT – File it in folder (either a folder that’s appropriate for that matter or just create one folder called To Do)
Urgent = High, Important = Low
If the email is Urgent but not Important (for your role) FWD IT – Forward the email to someone else (i.e. delegate the matter to somebody else) Then DELETE the email
Urgent = Low, Important = Low
If the email is not Urgent and definitely not Important (e.g. SPAM) - BIN IT – DELETE the email immediately. If you’re really not sure you could archive it.
Delete your Deleted Items
Your Deleted Items folder also contributes to the size of you Outlook File. If you right click and select Empty Folder you may receive a warning that you are about to permanently delete your deleted items - if you are sure proceed - this will help reduce the size of your mailbox.
Archive your Email
As previoulsy stated - in Outlook all of your emails, email attachments, folders, contacts, calendar and tasks are stored in one file. Setting up an Archive ensures that old emails you still wish to keep are moved from the live file into a separate second one (usually called archive.pst) Unfortunately this is not available on a Outlook for Mac.
If you have Replied Delete It!
One further tip to help you clear your inbox. If you see this reply arrow on an email in your inbox...
...then DELETE IT!
If you think about it, the original email you replied to will be in the reply you wrote in your Sent Items folder - so why is there any need to keep the email you have already replied to?
Unsubscribe from Mailing Lists
If you have ordered from a website you may have unsuspectingly signed up to a mailing list. GDPR rules mean that the organisation mailing you need to make it easy for you to stop receiving emails.
Look carefully at the foot of your email and you should see a link to Unsubscribe or Stop Receiving Emails.
Be careful though. If it has come from an unrecognised source and is truly SPAM - do not click the link as this will confirm you have a live email address and could invite further SPAM.