Many guards use a portable radio or telephone that allows them to be in constant contact with a central station outside the guarded area. If they fail to transmit an expected signal, the central station investigates. Guard work is usually routine, but guards must be constantly alert for threats to themselves and the property they are protecting. Guards who work during the day may have a great deal of contact with other employees and members of the public. Some employers have three shifts, and guards rotate to divide daytime, weekend and holiday work equally.
Guards usually eat on the job instead of taking a regular break away from the site.
They should be mentally alert, emotionally stable and physically fit in order to cope with emergencies. Guards who have frequent contact with the public should be friendly and personable. Some employers require applicants to take a polygraph examination or a psychological profile. Many employers require applicants and experienced workers to submit to drug screening tests as a condition of employment. To be licensed as a guard, individuals must generally be 18 years old, pass a background examination, and complete classroom training in such subjects as property rights, emergency procedures and detention of suspected criminals.