The two most common definitions are “own occupation,” where a person is considered disabled if they are no longer able to perform the occupation they had prior to becoming disabled, and “any occupation,” where a person is considered disabled if they are unable to perform any job at all. Obviously, the “any occupation” definition is stricter. All else equal, the policy with the stricter definition of disability will be the cheaper policy because there is less of a chance of an insurer having to pay benefits under a stricter policy.