Carefully read the wording of what the policy defines as a disability. Own-occupation disability is the most desirable definition as this indicates if you cannot work in your particular job due to a disability you can still collect the insurance even if you do find part time or even full time work at a lesser paying job that doesn't have the same physical requirements.
Any occupation disability insurance policies are much more restrictive but tend to be lower cost. This type of policy will only pay out if you cannot work at any type of job, even if the job is not even close to your current profession. These types of policies may be very limited as to the conditions that they will actually pay out under.