The passage of time in Pantheon is measured in ages which can either be rigidly structured units, or vague developmental periods. Below are some suggested ways to pace the ages in your game.
Number of in-game units of time
The most common amount is 100 year blocks. This works well for already established worlds. the passage of time is generally tracked and noted by the GM. “It has been thirty years since the beginning of the Age”
Number of Real-Time Units of time.
An age may be an hour or an entire gaming session in real time, and span anywhere from millions of years to a decade in game-time.
Number of turns or actions
After each player takes so many actions, it may be the end of an age.
Usage of GP
An age could be ended when the players are low on GP.
At the end of a story arc
When the gods have resolved a particular set of problems or a conflict.
Carrying GP over
Some Gods may have GP left from previous ages when an Age resolves. The GM may wish to set a maximum amount of GP that can be carried over to discourage stockpiling or not.
Whatever method you use, end the age when it seems right.