Chosen answer:Officer Don ended up appearing in 100 of 139 episodes, but I would say season 3 is when he become permanent as Wayne Knight's name appears in the opening credits. However, as he did appear throughout season 2 (first appearance S01E17), it's possible they already considered him permanent at that time since season 3's opening credits also included Simbi Khali (Nina) and Elmarie Wendel (Ms. Dubcek).
Chosen answer: Officer Don ended up appearing in 100 of 139 episodes, but I would say season 3 is when he become permanent as Wayne Knight's name appears in the opening credits. However, as he did appear throughout season 2 (first appearance S01E17), it's possible they already considered him permanent at that time since season 3's opening credits also included Simbi Khali (Nina) and Elmarie Wendel (Ms. Dubcek).
Bishop73