Mental capacity is assessed based on the ability of a person to make a specific decision at the time the decision needs to be made. The assessment should be carried out when the person’s capacity is in doubt and he has to make a particular decision. A person is unable to make a decision when he cannot do one or more of these things in relation to making a specific decision at the time it needs to be made: (1) understand the information; (2) retain the information; (3) weigh up the information; and (4) communicate the decision. All practicable steps must be taken to help the person make his own decision. If the person lacks mental capacity to make a particular decision, then the decision-maker must act in the best interests of the person.