How often should the transmission fluid and filter be replaced on a 2002 Nissan Maxima?

The 96 Maxma has a timing chain which lasts the life of the car. I have a 112000 on mine and it runs fine . I am doing mine and I have 12000 when the belt starts to crack or make noise it is good to change it. The belts are not that much. I found mine on line for $12 and I would rather spend that than have it break down and then pay to get it towed.