The document, marked “Law Enforcement Use Only” and dated August 2010, illustrates there are some significant differences in how long carriers retain your data.
Verizon, for example, keeps a list of everyone you’ve exchanged text messages with for the past year, according to the document. But T-Mobile stores the same data up to five years. It’s 18 months for Sprint, and seven years for AT&T.
That makes Verizon appear to have the most privacy-friendly policy. Except that Verizon is alone in retaining the actual contents of text messages. It allegedly stores the messages for five days, while T-Mobile, AT&T, and Sprint don’t store them at all.