The recreational solo diver uses enhanced procedures, skills and equipment to mitigate the risks associated with not having another diver immediately available to assist if something goes wrong. The skills and procedures may be learned through a variety of effective methods to achieve appropriate competence, including formal training programmes with associated assessment and certification. Recreational solo diving, once discouraged by most training agencies, has been accepted since the late 1990s by some training agencies that will qualify experienced divers skilled in self-sufficiency and redundant backup equipment.