Apprenticeship training requires both on-the-job work experience and related instruction. On-the-job work experience is provided by the registered sponsor and is organized and systematic. Related instruction is designed to provide the apprentice with the theory and technical knowledge related to his/her trade or craft. Local vocational technical schools, the sponsoring organization, or the local community college may provide related classroom instruction to apprentices. A registered apprentice completes a minimum of 2,000 hours of supervised on-the-job work experience in a specific occupation, and a recommended minimum of 144 hours of related instruction for each year of apprenticeship. Depending on the occupation, the length of apprenticeship varies between one and six years, with four years being the average.