Town growth and unit recruitment?

[Shika_mech]

Ive had this game for years over 500 hours on it. One thing Ive never figured out is what does town growth do? Does it increase the amount of units you can recruit? If not how do you make town have more slots of recruitment? Do these apply to previous total war games? Town Growth and unit recruitment work very differently in Rome and Attila. I get what those do

[Greve Af Göteborg]

Town growth increases how much wealth your town brings in each turn (Town wealth). If you have a total of 10+ town wealth growth per turn, and you're currently making 1500 in income. The next turn you're going to make 1510.
You get more recruitment slots by upgrading your castle, I believe it goes like this: Fort (1 slot) > Stronghold (1 slot) > Fortress (2 slots) > Castle (3 slots) > Citadel (5 slots)
Citadel requires a civic arts technology that's very late game (Epic Architecture). But you can build the other ones from the very start of the game.
Upgrading the fort/stronghold/fortress/castle/citadel is going to take away food. So make sure that you have at least 1+ food before you upgrade.

[Weierstrass]

Only one thing, it will increase town wealth but only a % of it goes to iconme (example. if you add 10 but your tax is 20% then you add 2 to income)