[thejeff]

The primary use of forts is to recruit mages or to guard valuable provinces (chokepoints or very good magic sites). But mostly for the mages. Therefore, you usually want the cheaper/quicker forts. Admin value and defense are secondary.

As DeadlyShoe says, items are mostly used for building thugs/SCs. It's sometimes worth equipping mages for battle, almost never regular commanders. Maybe bows or spell casting items.