It's pretty common to manage more than one mailbox these days; there's your individual email inbox, and then maybe you have access to a shared mailbox such as an info@ mailbox. Because of the amount of emails you're going to be storing it's really important to be confident that any emails you send are filed in the correct mailbox.
I had an issue recently with Outlook 2010 and 2013 where an email from a shared mailbox was going into the default mail account rather than the sent items of the email address it was being sent from. This meant the client couldn't keep track of their emails properly.
A fix for this issue is to open the command line by going to the Start Menu > typing ‘command prompt' > selecting the command prompt icon> and once that opens you should see the below program appear.
For Outlook 2010 enter the below text:
Reg add HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Preferences /v DelegateSentItemsStyle /t reg_dword /d 1 /f
For Outlook 2013 enter the below text:
reg add HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Preferences /v DelegateSentItemsStyle /t reg_dword /d 1 /f
Then hit enter and reopen Outlook and your sent emails will then go into the correct mailbox sent items folder.
Be sure to backup you registry first just in case anything goes wrong.
If you have any issues leave me a comment below!