two different worlds when you are talking about text messageses versus emails.
Any email is stored on upwards of ten servers, so finding a deleted email is pretty easy (unless your the head of the IRS). An email is a message sent from a service (i.e. yahoo, Microsoft, google) through to another service an to multiple platforms, each one of those platforms saves a copy of it, so it is very easy to retrieve a deleted email.
text messages are very different, they are only on the two phones and the carriers server. If both phones are on the same carrier, it is even harder to find them once they are deleted. imessage (texts between two iphone users) are impossible to retrieve once they are removed from the phones. In fact they do not even appear on court ordered wire taps.
the carrier only dedicates a minimal amount of RAM for texts, and usually within two to three days, the text data is overwritten on the servers hard drive.
All of this is to show that Brady destroying his cell phone would have been a) useless because it's not like the NFL could come into his house and grab it b) useless because all he really had to do is delete the text messages and c) if there were emails they could be easily recovered from numerous servers.
I call BS on this story, because Brady's lawyers would have surely told him all of this right away.