J.P.
The gel deodorant is super easy to over use, but the stick really only goes on so much. It's hard to overuse it. I also suggest you teach him to use it whenever he dresses to avoid smelling. He won't notice it, and you might not at first, but other kids in his class will immediately, and kids can be really cruel about things like that. No matter if it only happens once, that one incident could stay with him depending on the kids who notice. Better to avoid the entire problem by starting deodorant early!