From Doomsday Wiki
Housekeeping is the passing of one month on the Doomsday world. All automatic calculations and control of Doomsday occur at housekeeping. The following events occur at housekeeping in order: 1. Farmers are taxed 2. Farmers reproduce 3. Scientists Research 4. Factories Produce 5. Troops paid 6. Movement Points Allocation
Also, -99 favour players are killed off and Quest flags are reset during housekeeping.