Tad and Chad are often seen hanging with other rich and popular students, notably Trixie Tang and Veronica, and encouraging others to scorn Timmy and the other unpopular students. They also tend to throw parties on their yachts along with the other popular students.
They can also afford useful gadgets such as jetpacks and motorbikes.
Weight GainEditWhile Chad hasn't gained weight at all in the show, Tad has once (although it was brief).
In the episode "Just Desserts", Timmy wished people would eat nothing but dessert, causing everyone to become overweight. Tad had a single, non-speaking, cameo appearance in this episode. He used a motorized scooter for mobility, which eventually collapsed due to his large weight.
In the original episode script (found here http://www.scribd.com/doc/15589147/223-Just-Desserts), Tad was going to have dialogue in this segment.