The short answer
Use guards when the site needs human judgment, interaction, access decisions, patrol, immediate communication, or a visible professional presence. Use cameras when the goal is broader observation, recording, investigation support, or coverage of remote and changing areas. Use access control when entry permissions, credentials, schedules, and audit records are central. Many businesses need a combination because each control has limitations.
What to know
For example, an electronic reader can consistently check a badge, but it may not recognize tailgating, distress, or a borrowed credential. A camera can preserve video, but it cannot physically guide a visitor or inspect a door outside its view. A guard can resolve exceptions and respond under post orders, but one person cannot continuously watch every camera, control several doors, and patrol a large property at the same time.
Start with the objective and consequences: who and what needs protection, when, from which risks, and how quickly someone must act. Then examine lighting, sightlines, power, network reliability, privacy, staffing, false alarms, maintenance, and law-enforcement response. Layer controls at critical points and define ownership of alerts and evidence. Arrow offers officers, patrol, integration with commercial electronic systems, and portable solar camera towers. Its proposal should explain how the layers communicate and what happens during an outage rather than selling each component in isolation.