Assistance dogs have traditionally been trained by charities and other organisations who then partner a disabled person with a trained dog when the dog has completed its training program at approximately the age of 2. Increasingly, more disabled people are self-training their own assistance dogs,[4] whereby the disabled person selects their own dog (often referred to as a 'prospect') and the dog is trained by the disabled person who also becomes their eventual handler. There is great variability between the length and type of training that any future assistance dog receives; however, all assistance dog candidates will go through certain stages.