I would assume when you can't qualify with your weapon or can't drive a car for starters. As a matter of fact, I'm assuming that most departments terminate officers that can't qualify with their weapons or can't drive a police car. My department has terminated officers for having too many traffic accidents and age wasn't a factor. Even if an officer is in an administrative position at a fixed post and out of uniform, he or she still should have to qualify with his or her duty weapon per state peace officer requirements. I plan on retiring when I'm 60 with approximately 35 years of service.