It depends on the complexity of your system, but it is a National Security Inspectorate (NSI) requirement that your CCTV is serviced annually.
The servicing should be carried out by a qualified professional that is verified by a third party body, such as the NSI.
We also recommened checking your CCTV on a monthly basis looking for signs of damage or wear on both the cameras and cabling, making sure all signage is clearly visible, and ensuring all equipment is protected against vandalism or tampering.