The only things I can think of that I don't see specified above:
Relationship culling - your sims' relationships will decay over time and be culled. In my family rotational save, my original sim was always forgetting her sons/daughters-in-law to make room to remember the random person she met while I was playing someone else on a community lot. They don't forget parents, children, siblings or grandchildren but they do forget cousins and in-laws and I'm not sure about aunts/nephews. I now use MCCC to completely prevent culling and manually delete relationships that my sims pick up randomly that I'm not interested in keeping up.
Sentiments - When you rotate all sentiments will go away. I actually like this because it gets rid of the annoying ones with no work on my part, and the positive ones usually come back pretty quickly. One date will usually restore the romantic ones. I am still wondering if this is also true with Lifestyles because I don't have SE yet.
Eco Lifestyle - If you don't turn NAP voting by npcs off in the game settings, and your sims' neighborhoods don't have the max number of NAPs already enacted, they will vote in new ones while you are playing the other households. This can be a problem if say you have a household that lives near a park and they vote in free love and the next time you take one of your other families to the park there's people walking around naked. You can only remove them while playing the household that lives in that neighborhood. If you turn voting off you can still have your active sims vote, they just always get what they want because no one else votes so there's no challenge to it.
Oh, and don't bother having your sims do their homework or daily work tasks on the last day of your rotation because it won't count anyway, except for boosting responsibility if you have parenthood. It will show as not started when you rotate back. Also if you like to have your sims work from home, make sure they go in to work on their last workday before you rotate so they get their pay/advancement at the end of their shift. As you know if you play these jobs, work done at home doesn't get credited until the beginning of their next shift, and if you rotate away before that happens they just don't get it at all.
And I guess you might not want to have holidays scheduled on Fridays if you're going to rotate Friday evenings, or just ignore them or end them early, because if you rotate away while they are still going on you don't get any rewards.
Personally I have aging off except for the played household because I don't want them to have birthdays without me. On the other hand I let babies be born after I rotate all the time, and just change the name in CAS when they age up to toddler. So that kind of thing you just have to decide what your personal preferences are.
