Units pop at the start of a Side's turn, as part of the normal production of a city. Units pop with a set of non-magical equipment such as standard armor, weaponry, and clothing. Cities may randomly pop extra units, requiring the Ruler to decide to pay a one-time extra cost or disband the unit.
Rations and Unit Upkeep
Units receive physical food rations and other objects required for their daily functioning at the start of their turn. These objects may be consumed at any point in the day, or saved.
Barbarian units may also pop randomly in non-city hexes. Non-unit wildlife pops commonly, with the type, number, and frequency of the plants and animals dependent on the Terrain Type. Magic Items, Artifacts, and Gems may pop randomly in Ruins or the sites of sacked cities.
The disappearance of objects is called unpopping. This happens automagically to corpses of Croaked units which are not Uncroaked, eaten, moved from the city or hex where they were croaked, or claimed as trophies. The disappearance of living units is called disbanding.
Food pops at the beginning of each day/turn. Assuming the side can pay for the upkeep of its units, every unit will automatically pop enough food to nourish it for that day. Food appears already cooked and needs no preparation.
Units, including Royal and Noble units, and presumably casters as well, all pop in cities after a certain period of time. Warlords can be popped, but doing so takes a long time, and as they can be designated, or promoted, from regular units, this means that the length of time needed for popping a warlord can be put to use popping normal unit.
Units can pop at random outside of cites as barbarians.