Catplayz
YES AN EXUSE TO TALK ABOUT INCOME.
Right, really we are all wrong here, as if 8 billion people paid 1c per year you would be getting around 26,000,000c per day, so really, in terms of money, make as many as possible.
However it kinda depends on the amount of systems owned, population and many other factors:
A group of peace loving space plants might build maybe a few warships. And that is it.
A group of normal "in the middle" people about war, might make around half their capacity for a fleet.
Whereas a war mongering civilization would be likely to build as many as possible.
this is a good example. it is from a ww2 game, but it still applies here.
However, in terms of the Rp side of things, I don't know, my faction with around 10 billion people (yeah its tiny) has around a capacity of 10 flagships, 40 capital ships/cruisers +some corvettes and loads of drones.
And really, unless you want to go to war with loads of people, you only need a small fleet to participate in most things on the forums. (at one point I had a tiny frigate and two cruisers and still played an integral role in an event)