In Age of Empires 3, one can revolt from their home city (for a non asian civilization) in the industrial age.
This converts all villagers into fighters. While factories and banks keep producing money, the economy is usually at a standstill. You get infinite shipments (you can even take infinite shipments of forts) and a small army the second you reach the revolt stage. You still can produce army, but with the limited economy this is not too effective.
I've never been able to make this useful; while it may temporarily stop you from losing it rarely ever gains you the upper hand.
When should one advance to this age?