ADT uses a cannon fodder system when it comes to outside salespeople - hire 'em cheap, stack 'em deep, and see who survives the first 90 days. If you can tolerate that environment, you can make some money down the road.
But it will cost you - working 6 days/15 hours per day, grinding your car into junk, and facing a constant barrage of "motivational" insults and abuse delivered in person, by telephone, and email by your "manager" who will usually be an Roger Ramjet ex-military and/or law enforcement type.
I was making decent money but left for another opportunity due to the poor treatment new sales reps receive from technicians and support personnel. To them, you are just another FNG until you've been there a year or so, and not worthy of their respect or common courtesy. Customer service and support is also not up to the standard that ADT leads the public to believe, and many of these issues are left up to the salesperson to resolve. That would be fine, except that you are paid straight commission on new business only, not to do customer service and tech support after the sale.