What is the point of the persistent repetition of the words "the things they carried"?

O'Brien uses the repetition of these words to create an unmistakable realization that the men are always carrying “things,” whether it is a physical weight or an emotional weight. The repetitiveness of the words lets the reader, in a sense, feel how the soldiers feel. The soldiers are unable to forget the weight of the “things they carry,” and by repeating the words, the reader is not able to forget the weight either. The sense of annoyance that the reader may feel by the constant repeating of the words is a technique used by O’Brien to connect the reader to the characters. The soldiers may also feel frustrated that they do not get a reprieve from the constant burden of their weights.