An own occupation provision, is the most favorable to an insured to have in a policy. With own occupation, the insurance company is going to constantly look at what job you were performing at the time you became disabled.
What one needs to understand is, you may have bought the policy 20 years ago and you were practicing medicine at that time. However you had a change of careers, you decided you wanted to pursue something else, and for instance, you decided to become a bricklayer. You become disabled at the time you were a bricklayer. The insurance company is not going to look to determine whether or not you can be a doctor any more, they are going to look at whether or not you can be a bricklayer. So own occupation will carry through constantly in transition. Maybe you bought the policy when you were a bricklayer; you went back and became a doctor. They are going to review it as if you were a doctor.