For projects lasting longer than 30 days, or involving more than 500 person days of construction work, clients must appoint a CDM co-ordinator. Their primary function is to advise the client. The CDM co-ordinator will be able to advise the client on the appointment of competent dutyholders – assessing the adequacy of other team members’ management arrangements for the project, and the adequacy of the health and safety plan. The client is entitled to rely on the advice of the CDM co-ordinator when making their judgements.