This is the 3rd Messenger Bag I have purchased for my son.  They seem to wear remarkably well, however if you plan to carry more than 2 or three books in it the strap will eventually come off.

My son loves the style and the adjustable strap.  It does also hold all of his pens, pencils and paper supplies comfortable.  For transporting a few every day school supplies it is perfect--just don't overload it.