Lately I've been playing Caesar 3, and I've gotten to the point that I'm pretty good, but I need to know more about how the game works if I want to progress. I came across this video, which actually had some great information in it. However, at about the 49-50 minute mark I noticed something interesting.
Basically, you have about 20 or so in game years to win the map before your economy gets fucked. The reason being is that it models your working population as 21-50 yoa. Initially your immigrant population is going to consist almost entirely of workers and working age people. Eventually though they all start to age, in which case they cease working yet continue to require valuable resources. The replacement population doesn't compensate for the aging population however.
One option is to continually expand, which in turn creates increased demand and requirements for things like access to entertainment and religious sites. This isn't a bad option, but there are some maps that severely diminish your habitable space. So sometimes you end up at a maximum area sooner rather than later.
Another option he offers is curtailing the quality and availability of health buildings, barbers, doctors, baths to decrease your health/prosperity rating, and by doing so diminish their longevity. The sooner they die, the sooner they free up space for a working immigrant to move in, increasing your economy's efficiency.
Now, why does that sound so familiar? :^)