I'd recommend to wax your car once in a three - four months (the often, the better) after washing. Wax helps to protect the paint, minimizing harm of chemicals and protecting the paint from fading; plus the car looks shiny. It takes about 30 minutes to wax a whole car and high quality car wax stays on the car for three - four months. So far, I haven't seen a single product that stays for life time as you might heard in some commercial - nothing lasts forever. In order to maintain protective coat any product needs to be reapplied periodically. For example, from my experience, the Turtle Wax Carnauba wax stays for three - four months.