Well, I don't set a lot of rules for my game. There are some I have set.
One rule I do is that until adults have children their aging is turned off (with aging off cheat). Reason is simple: adulthood lasts 29 days while baby to teen stages last 30 days. Plus additional 3 days from pregnancy.
There is always an apartment building in my neighborhood that is designed as retirement home. Every retirement home household consists of one adult (a caretaker who is immortal with the elixir of life). As apartments can have up to 4 households, each retirement home can hold up to 28 elders. If elders live in an apartment, the must move out to the retirement home. If elders live in a house, it's my choice whether they live the rest of the life in their house or in the retirement home.
For some games, I have a main family. After playing with that family, I write down how many days I have played with them and play the same amount of days with other families. Once their days are up, I'm allowed to rotate. Days count while sims are either at home or on vacation. Once all the other families are caught up with, I'm allowed to once again play with the main family.
However, there are some things that affect how many days I play with a family. If the household has only elders or parents whose children have moved away, the amount of days I play with them is two times less. If a family moves in, I can play with them one day less. If a family is on vacation when I last left them, they get extra days depending on how many days are they on vacation. If I have played less than three days with the main family, all the college households get three days. Should I accidentally or on purpose play with an household overtime, I'll write down the amount of days I played over so I can play that amount less next time.
For notes, I use two things: an electronic device to count the days and family/household description to write down whether they're not played with, are currently being played with, or have been played with (with numbers of course).
Though these rules do have their own cheesing moments. For example, if I want a sim to graduate faster, I send them to a college community lot so their semester finishes up faster while the day counter stays the same. If I want to keep sims from aging up, I send them on vacation.
Sometimes the neighborhood story is used as a newspaper. If that's a case in a game with a main family, I have to write 5 stories before rotating back to the main family. After that, it's fun to see what other sims have done. Perhaps someone found a treasure. Maybe a businessperson got "The Best of the Best" award. Or maybe, just maybe, there was a sim who didn't live in the apartment building who only drank bar drinks for days and had bladder failures as he was too focused on the bar.