When gas is used correctly and with respect it is a safe and economical fuel. However - as with any area of expertise - people working with gas need to have the appropriate training and experience. CORGI-registered installers have to undergo at least the minimum requirement of training before they are accepted on to the CORGI register. Most have significantly more training. The training and assessments that registered gas installers have are not only about the technical know-how of specific appliances but also about safety. All assessments have to be renewed every five years in order to keep installers up to date with ever-changing standards and regulations and to keep their knowledge fresh.