You can cut or tear from any part of the plant without harming it. Any area that touches a hard surface can attach itself. Its very easy to grow and can become a problem in some tanks if its not kept in check. I've never seen any of my own die and its existed in my tank for several years so I don't think you need to worry about it dying of old age.
You can find your own quotes in this article.
Halimeda: The Cactus Algae
http://reefkeeping.com/issues/2004-04/nftt/index.php