This is a difficult question to answer. There are many factors that come into play when considering how many times you can suspend a T-Mobile line. The main factor is how long the suspension lasts, which will determine what happens with the account. If the suspension lasts for less than 30 days, then all of your messages and data will be preserved in accordance with T-Mobile's Terms of Service. If the suspension lasts for more than 30 days, then messages and data may be deleted.