The tight schedules that announcers work on can be stressful. Although most announcers work full time, many work only part time. Many radio and television stations are on-air 24 hours a day. Some announcers present early-morning shows when most people are getting ready for work or commuting. Others do late-night programs. The shifts, however, are not as varied as in the past. Technology has allowed stations to eliminate most of the overnight hours, because shows that air during the night can now be recorded earlier in the day. Some self-employed announcers record their shows at home and sell them to networks and stations, advertising agencies, or other independent producers.