I realize what I have seen is on a Law and Order or CSI show-

But, if LE gets a warrant to review your phone records (non-hobby phone ) are deleted text messages kept in the carrier's database? In other words, not just that you sent a text to someone, but the content of that text.

Like a computer, they are still there until overwritten.  There are over write programs for computers.  I don't know about overwriting phones.

Depending on your carrier, & what kind of phone you have, a lot of the newer Andriod type phones no longer come with SIM cards... some do, some don't. So, not sure in cases such as these?

The new smart phones my investigators and I have dealt with have hard drives.  Data can be held in memory which is later get be accessed like ROM (Read Only Memory) but data must go to a storage device for long term a sim card a drive of some sort.  They don't have removable drives, so it's on a fixed hard drive.  Some like the IPhone is now somewhat water resistant. However, drying out a hard drive can be done anyway some times. Text have been recoverable as evidence for awhile, if that's what you wanted to know.  Stick to talking.  

There are books on electronic privacy.  It's an industry.  What's needed for you guys is a specific book &/ or a seminar.   Somebody out there must be able to work with my specialist on a book directly aimed at at the hobbyest concerns with electronics.  Volunteers?

I know of a case where a cop was being investigated for committing a crime.  The cell phone company was subpoenaed for records, they provided a huge stack of papers with every text message that was ever sent or received on his cell phone.  So it would certainly appear that every text message was saved indefinitely by the cell phone company.  The funny thing was that this cop's text messages also showed that he was having an affair with some other cop's wife while he was supposed to be working.  So he was fired.  If he has done his research on this website, he would have known to use a second "hobby phone" instead of using his employer issued cell phone.  haha.

carriers and how long they keep messages (years) also about the thousands of times they've turned them over to the Feds. Obviously most have to do with terrorism and drugs but there is nothing right now that stops them from obtaining them on anyone. O'Reilly even did a piece on it and mentioned some politicians who are trying to put a stop to the ease of access the government has to our text and emails.

When I was a teenager my grandfather who was well read, but never went past high school to my mother's knowledge was quite a philosopher.   However, one time he gave me some advice that I thought was aimed at my age and his times:   "Be careful where you put two things in life.  Your signature and your pecker"

He never ever talked like that.  My grandmother acted like he didn't do that much either.  He could have been one closed mouth hobbyist,  He sure enjoyed a dirty joke when he heard one.

Therefore gentlemen,  don't put anything in writing you don't want to see in the newspapers.
I forgot who told me that.  A politician I bet.  I use to hang around with them but now I prefer prostitutes to whores.

http://www.ktul.com/story/20076252/petraeus-case-shows-fbis-authority-to-read-email?clienttype=printable  this law and google together are a trip 1986!!??!!??