Before the Second World War, ADC recruits were required to be at least 5 feet 2 inches (157 cm) tall and could enlist up to 30 years of age. They initially enlisted for seven years with the colours and a further five years with the reserve. They trained at the Royal Army Medical Corps Depot, Crookham Camp, Aldershot, before proceedings to specialist trade training. The two trades available at that time were Clerk Orderly (who assisted in the operating room and in clerical work) and Dental Mechanic (who worked in dental workshops).