Odds of Hanging On

Odds of Hanging On

 
This one's your call. (Source)

Once you're certified, you're pretty much fitness instructor for life. As long as your body (and mind) can handle the stress and people keep showing up to your classes, you've got a job. Just remember: If you become too aggressive, people will complain. Being personable goes incredibly far in this career, so know who can take it, and who requires a soft and gentle touch.