Story progression

Story Progression is an option in The Sims 3. It helps keep a town alive and balanced. With Story Progression uncontrolled Sims' lives progress normally. Neighbors may move away, new ones will move in, get promotions, have children, and even die.

Effects

 * Sims grow older with the player's Sims, letting them keep childhood friendships.
 * Sims will sometimes have babies.
 * Sims in any inactive/uncontrolled households can be moved out.
 * Sims in inactive/uncontrolled households can switch jobs.
 * Uncontrolled Sims do not complete wishes.
 * Sims will eventually die (their graves will not be accessible unless the active family receives a phonecall saying that they have passed on; to receive this call, either someone in the household must be friends with the newly-deceased Sim, or it must be a family member).
 * Sims will sometimes get married, though it's very rare.
 * Sims may become friends, rivals, enemies, or love interests.