Murphy was an optimist. I have repeatedly had problems with USB cables. USB cables are held in place only by the friction of the connector. Repeated insertions and removals WILL wear out a USB connector. Anyone with an old laptop has probably encountered this problem.
Another problem is in systems that get moved around a lot or are subjected to a lot of vibrations. Here is what I did to eliminate this problem in a recent project. Zip ties are wonderfully useful.