I think the deciding factor in how long you will be active and satisfied depends on how you got into EMS. Is being a caregiver something you've wanted to do your entire life, or is it a paycheck that your friend told you about for completing a single (woefully inadequate) college class? To be a little bit trite, did you call it, or did it call you? Don't get me wrong, everyone who does emergency medicine will go through low periods; how long the "funky times" last is totally a function of your personality and drive. For those who see it as strictly a "pay for performance" thing, once the siren song has faded, (pun intended) will there be enough left in the job for you to stay in the field? I'm not going to get into the whole "vollies are more dedicated because we do it for free" debate;' that's a topic for another thread and another day. Paid or volunteer, part-time or full, you will get out of it what you put into it. If your only reward is found on every other Friday, then you probably won't last; on the other hand, if caring for the sick and injured has been your dream since you were rolling a Tonka ambulance across the carpet in your parents den, you will probably be around for a long time.