I left the FD because I was offered a job at an airline.
If I had to do it all over again - I never would have left the FD. 18 days off a month. Starting pay (in 1997) was $41,000. I would probably be a Captain and/or Battalion Commander now making about $80,000 per year.
Very, very, very secure job. I always said that as long as there are idiots out there, I will always be employed (smoking in bed, drinking and driving, marital affairs where the wife puts a slug in the husband, etc...) My biggest concern was that people would start thinking and acting responsibly.
Not to mention that I would have been able to retire with a full pension at age 52.