I am a technology guy, but I still think it is wise to have some set age limit. Usually by the time students are in middle school or high school, you might want to consider it. By then they are in sports practices or after school programs and they may need a way to get in contact with you to pick you up. It is hard though. Smart phones are so powerful and accessible these days. The serve so many functions besides being just a phone. Mine is my book, my planner, my gaming system, my encyclopedia, my dictionary, etc. It may be wiser to reinforce proper digital citizenship as the time approaches for them to get one. If they view having a smartphone as a privilege as opposed to a right, it may make the difference.