I have ADT as well. I just bought my house a little over a month ago, so I've not had the service long. Though I can say that the response time is great when I forgot to deactivate the alarm. They called right away!
I happen to have three old timers in my "hood."They can tell me what time of the morning I get up to #&^%.
Sometimes look around at your local companies and see what packages they have to offer.
One company around here will do drive by's when you ask, I know because of the construction jobs we hire them to patrol.