Clients are often surprised when an agency quotes three or four guards for one gate. Here is the simple maths behind round-the-clock security — and why cutting corners leaves your post empty.
The basic maths
- 8-hour shifts: 3 guards cover 24 hours, plus a reliever for weekly offs and leave — about 4 people per post.
- 12-hour shifts: 2 guards cover 24 hours, plus relief — about 3 people per post.
- Every additional post (back gate, patrol, parking) multiplies the requirement.
8-hour vs 12-hour shifts
Eight-hour shifts keep guards alert, especially at night, and are simpler under labour law. Twelve-hour shifts reduce headcount but tired guards are less effective, and extra hours must be paid as per law. For sensitive sites, 8-hour shifts are the safer choice.
Supervisors and night checks
For sites with several posts, add a supervisor per shift or a roving supervisor who checks multiple sites. Night-time surprise checks are the single best way to stop guards sleeping on duty.
Frequently asked questions
Can one guard live on site and cover 24 hours?
A single “resident watchman” cannot stay alert for 24 hours and this arrangement often breaks labour rules. It is not a substitute for proper shifts.
Do I pay extra for the reliever?
In a per-post quote the reliever cost is usually built into the rate. In a per-guard quote, ask how leave cover is handled.
Related guides
- Security guard cost per month (2026)
- Security guard duties checklist
- Security guard services: complete guide
Need a 24x7 security plan? Shiv Security Service is a PSARA-licensed security agency with police-verified, trained guards and 24/7 supervision. To get a free site survey and quote, book security staff online, use our contact page, message us on WhatsApp or call us.