Sent box empty

When I go to my 'sent box' I get this message
'

Sent Items contains 0 messages. You have 5 messages stored, of a total 60 allowed.
(Empty Folder)'


I have sent messages but usually as a reply to to an incoming message. Do these not appear as a sent message?
I cannot check on my sent message until the recipient replies to me and then it is at the bottom of the conversation.

the default is to NOT save sent messages. You must set it on a message you sent for a copy to be retained.

This isn't an email system ;-)
Edit: yep you can change teh default if you cared.... limited storage space that you never remember to visit before it fills up and causes you a problem

If you select Settings at the top right then select General Settings under My Account, you’ll then see a check box to save a copy in your sent messages, then scroll to bottom of page and save changes

Thanks and done.