The only things he deletes, as far as I can personally tell, are when he makes a typo and then replaces with a corrected tweet. And I now believe those typos are almost always intentional. If you notice, almost all of the typos are on tweets where he is making a very important point that the media is NOT covering sufficiently. This causes the media to hyperfocus on the typo, thereby giving it oxygen and making the media rounds. Brilliant media tactics by Trump.