These rules were found on The Sims 4 Three Little Sims Challenge — The Sims Forums
The Basic Concept:
This challenge follows the lives of three sims cohabiting the same lot. Using a rotation schedule of three days, you will control each sim just one day in three. The other two days, they will live their lives on their own; they will choose whether to go to work, make dinner, or hang around in their skivvies.
The Set-up
1. Create a family of three adult or young adult sims in CAS. You may assign the traits and lifetime aspirations as you like. The three sims should be roommates, nothing more.
2. Create a lot for the three sims to live on. The total cost should not exceed your starting amount of cash. The lot should include three separate homes, each with all of the essential items. Each home may also have a bookcase. No other fun objects or skill builders should be present on the lot. Set your funds to zero after building the houses. To do this, open the cheat console and type “testingcheats true” (no quotes), hit enter, and then type “money 0” (again, no quotes). This is TS4’s version of familyfunds i suppose (sure is a lot easier to remember…)
3. Move the sims into the lot and assign them their homes. For storytelling purposes, this is their “house.” Of course they will move in and out of one another’s homes as you play because there is no way to mark a house as theirs, but careful photo work can give the feel that each one has his/her own home. EDIT: You may add a communal dining area outdoors (i.e. a picnic table) once you have the funds to do so.
4. You may control the sims for the first day (through 8 a.m. the next morning). In this time, you should get them each a job. I would also recommend doing some cooking to try to build up their skill in this area so they do not set themselves on fire the first time you turn your back.
5. At 8 a.m. on Monday, you should begin focusing your work on just one sim. You may direct him/her to your heart’s content. The other two sims should be left on their own to do as they wish. I would recommend checking in on them from time to time to see what they’re up to, as this is where many of the ideas for any stories will come from.
6. At 8 a.m. on Tuesday, switch to the next sim. You will continue to use this 8 a.m. time to mark the beginning of each new day. The rotation should stay the same throughout the challenge. Sim 1 will always be Sim 1. There should be no changing the order around once the challenge has begun.
The Rules:
1. Sims should only be controlled on their assigned day. No keeping the tinkerer from electrocuting himself! If a sim is on fire, the sim you are controlling may run to extinguish it. If the sim you are controlling starts a fire or is on fire himself, you may attempt to stop his panic and put out the fire. If he continues to freak out, just hope the fire department is timely. (Please make sure to include a smoke detector in each home to help keep those simmies alive!)
2. You will need to keep a running tally of each sim’s bank. Once per rotation, you may spend the money an individual sim earned on something for his home. Consider wants and career promotions in these purchases. Don’t forget to leave some money so that the three little sims can pay their bills (oh, those Sims 4 bills).
In playtesting, I’ve found it very difficult to track each sim’s earnings, so if you would like to opt out of this rule for a more commune style of playing, where all money is pooled, that’s fine. If playing this way, only the active sim that you are controlling can buy items and they MUST be for the sim’s own house.
3. You may move in other sims and even get married. However, these sims should not be controlled. Only the original three are controllable sims for our purposes. This is also true if a sim chooses to have a child. (The decision to have a child will be a burden to all controllable sims on the lot. If a particular child is getting low on needs you may click on the sim to find out what is wrong and ONLY the current sim you are controlling may meet this child’s need so the social worker will not come to the lot.
4. If a sim autonomously finishes a painting when you are not controlling him/her, you may move it (either sell it or hang it in their home) so that he/she can use the easel again if the mood strikes.
5. You may move a sim who is stuck somehow, even if he/she isn’t the active one you are controlling at the moment.
6. You may use any life expectancy for the challenge. If you are keeping score, please just include the length of game you selected.
7. When you are controlling a sim, he/she should only use objects in his/her own house. What they do when you are not in control, however, is totally fine.
8. This challenge ends when all three of your sims die. If you’re playing with aging off, congratulations on creating a never-ending challenge!
Purpose:
To see how successful our sims can be on their own. To hopefully laugh at some silly things along the way. To serve as a distraction from other, more difficult challenges and projects. To declare a “winner” of our three sims and maybe compare scores with other players. If you’d like, you can declare the first sim to complete their lifetime aspiration the winner of this challenge. (Thank you to Glimmer50 for suggesting this idea!)