I use a setup where I save my sent-mails in my Inbox. This gives me the cabaility to have a threaded view on the messages including my sent-emails. To make this more readable, I defined two macros in ~/.mutt/keybind. One is to only show messages which are not sent my me and are not deleted (the "w" macro). The other macro is to show a thread including my sent-mails. Just select a specific email and press "=" and you see the thread including your sent-mails.
macro index w '.*l!~D !~f my@email.com'
macro index = 'l ~T !~D'
