What must flight instructors still do despite the removal of expiration dates from CFI certificates?

The correct option highlights that flight instructors are still required to complete specified activities to maintain their privileges even though CFI certificates no longer have expiration dates. This is important because, while the removal of expiration dates simplifies the status of a flight instructor's certification, it does not eliminate the need for ongoing proficiency and adherence to regulations.

Flight instructors must engage in continuous professional development, which may include teaching a certain number of flight hours, participating in training seminars, and staying updated with regulations and safety practices. These activities ensure that instructors remain competent and knowledgeable in their field, ultimately benefiting the students they train and maintaining safety in aviation.

The other choices do not accurately reflect the requirements for maintaining CFI privileges. For instance, stating that nothing is needed or that the privileges are automatic undermines the importance of a flight instructor's active role in their profession. The need to retake initial certification examinations or to lower insurance premiums doesn't align with the core responsibilities tied to maintaining instructional credentials.