Jobs can be categorized, by the hours per week, into full time or part time. They can be categorized as temporary, odd jobs, seasonal, self-employment, consulting, or contract employment. Jobs can be categorized as paid or unpaid. Examples of unpaid jobs include volunteer, homemaker, mentor, student, and sometimes intern. Jobs can be categorized by the level of experience required: entry level, intern, and co-op. Some jobs require specific training or an academic degree. Those without paid full-time employment may be categorized as unemployed or underemployed if they are seeking a full-time paid job. An activity that requires a person's mental or physical effort is work. If a person is trained for a certain type of job, they may have a profession. Typically, a job would be a subset of someone's career. The two may differ in that one usually retires from their career, versus resignation or termination from a job.