Good employers are pro-active with regard to health and safety practice including all aspects of Occupational Hygiene and Occupational Health. By contrast, poor employers too often assume everything is satisfactory until an incident or injury occurs. They therefore react to the incident after the event which for some is obviously too late. For this simple reason, all health and safety legislation in the UK is based upon proactive assessment rather than reactionary.

Some of these review intervals are specified in the appropriate Regulations, while others are recommended in the associated HSE Guidance Notes, Approved Codes of Practice (ACOP) or BS/ISO Standards.