Of course, the answer, as always, is that it depends. But, I not going to leave you with that. There are basic rules, and clues that you can read. For example, a standard answering machine message is set to record a standard message. If you always run to the end of the time limit, that’s a good clue that you’re talking too long. A voice mail or answering machine is set up to take basic information. Your name, your number, a brief reason why you’re calling. Maybe, to make life easy for the other end, you can repeat your name and number. Don’t give a bunch of reasons, don’t share all the details, don’t have the conversation without the other end there to listen.
It’s the same with emails. Take a look at a series of back and forth email correspondence. Is your answer always the long one? Does your email go to auto shutdown when you’re writing? It’s an email, not a thesis.
If you’re speaking face to face, the clues are a bit more direct, and easy to read once you know how. If your listener is nodding, saying things like “um-hum” or “yeah” that’s a good clue that they’re listening. If they look around the room, over your shoulder, or at their watch, you’ve lost them. Stop. (Maybe they’re captivated by your topic, but they just need to make sure they’re not late to pick up the kids. That’s OK. You should still stop talking. If they want you to continue, you’ll get a very solid clue like, “Go on, what were you saying?”)
When people are interested in your topic, they should be asking questions, or contributing from their point of view. That’s great, it’s a sign that the conversation is flowing well.
Which of course, leads right back to the idea of eye contact. Part of the reason that the speaker periodically looks at the listener is to gauge if they’re still listening. If eye contact is tough for you, you can still look over at the forehead or eyebrows.
Finally, the basic rule is that the closer the relationship, the more intimate the details you share. So it’s probably OK to tell your mom about your latest bout with the flu, but for the office, “I’m feeling much better, thanks!” may be just right.