Kata (forms) teach students structure and form of movements and techniques. They also keep both the theory and practical aspects of self-defense in the forefront of a student’s awareness when coupled with hours of practice. Basic forms do not necessarily provide realistic self-defense applications as they are practiced but do provide a framework for the theory and variations of technique that is needed on several levels. Usually this is addressed by a knowledgeable and experienced teacher.
Kumite (sparring) teaches the student the safe aspects of combative interaction. It is not a fight since it has rules and limitations for the safety of the practitioners. Sparring introduces and reinforces proper distancing, timing, angles, and decision-making.
Students can intensify their training and practice by testing themselves in competitions or shiai. This is a personal choice and not mandatory but it is usually considered a positive experience for students to get the feedback that a competition provides. It points out the parts of training that a student needs to improve, including mental and emotional control.