Three-fourths of licensed practical and licensed vocational nurses worked full time in 2010. The rest worked part time or on variable schedules. Many LPNs and LVNs work nights, weekends, and holidays because medical care takes place at all hours. They may be required to work shifts of longer than 8 hours.
Source: Bureau of Labor Statistics, U.S. Department of Labor, Occupational Outlook Handbook, 2012-13 Edition