Ends of the leaves of lucky bamboo drying out and turning brown
Unless there is another problem, the browning of the tips is caused by low humidity. This is understandable because the lucky bamboo plant is a tropical rain forest plant where the humidity is high, like 60 degrees and higher. So people living in Arizona or anywhere else should expect a brown tip or two. (Humidifiers cannot be turned up that high!)
An occasional misting with warm water would be appreciated by the lucky bamboo, but unless it is a problem with many of the stalks, it probably is not necessary. Moving the plant from a drafty location to an area where the humidity is constant would help. Lucky Bamboo will adapt well to low humidity if provided with plenty of clean water. The brown tips can be trimmed with a sharp scissors. Trim at a diagonal to from a point and the plant will form a scar that is barely noticeable.