All models in a unit should as much as possible be armed with the same weapon and armour type for ease of distinguishing their armament. Some variation is acceptable, but it should be clear to the opponent what sort of equipment a unit has. In case it might not be
apparent at first glance, this should be clearly declared upon deploying the unit.

If a model has more than one weapon, they must choose which weapon they want to use at the start of the shooting phase or close combat. A model cannot choose to use two different weapons in the same shooting phase or close combat unless clearly specified. However, if the model has multiple crew or riders (like chariots or ridden monsters), each crew or rider may use one weapon each as normal. Whichever weapon they select must then be used for the entire close combat, unless the weapon they are using is somehow destroyed – it's no easy thing to change to a different weapon partway through a fight.