The system may prescribe rules governing the recognition of agents or other persons representing claimants before the system, and may require of the agents or other persons, before being recognized as representatives of claimants, that they show that they are of good character and in good repute, possessed of the necessary qualifications to enable them to render the claimants valuable service, and otherwise competent to advise and assist the claimants in the presentation of their cases. Claimants may be represented by counsel at their own expense.