Selling a customer a new vehicle is just half of the battle. Losing customers to a competitor once they are ready to replace it is far too easy. Customer retention is one of the biggest struggles dealerships face.
You will drastically increase your chances of selling your customers their next car if you stay in contact with them for the entire time they own their current vehicle. The key is to strike a balance between communicating with them just enough and overdoing it to the point of irritation.