Email can be an effective tool to communicate in the office, but sometimes long chains and back and forth messaging makes it inefficient. In this case, it is better to just pick up the phone or set an in-person meeting. Phil Simon, the author of Message Not Received, recommends the “three-email rule.” "Put as succinctly as possible, after three messages, it’s time to talk. In my email signature, you’ll find that very rule…," he explains. "I abide by a three-email rule. After three, we talk."