Vanilla with no cheats ever - rotational with many households as well as with Maxis families and my own sims. I control aging of every one of my households and Maxis households.
In my own household I start with a ya - give it basic skills , career, and start them off, and then move to another lot, add another YA, do the same, and so forth. When I have about a dozen housed and started YA's I start rotating the play - adding in a day or two play with different Maxis households as needed - adding wardrobes, jobs if needed, skills, making friends with my sims, etc. Also as needed I add in more single YA households hoping some start forming love interest in other unmarried sims and eventually form families - in one of the sims houses. As I move sims in together I add another new YA to the abandoned houses. I build up my rotations a few at a time - all on one save - which I back up periodically. As I said I try and incorporate most of the Maxis Sims as well into my play - especially all the old Maxis favs first and then start adding the newer ones to to my rotations.
My worse problem in the Sims 4 is lack of affordable lots for all the YA's I want to start out. The new world was no help at all as i had 5 households I needed to move there with only one lot available - so I didn't buy it. I am tired of buying worlds that offer no room for my sims no matter what greatness they offer. Characters need homes to live in. other wise what is the point of having a game about life if all you can do is watch it like a movie and not have a base to play it like a game? I don't want excuses why an empty lot is a performance issue in a game they have "YEARS more content planned for" their words - not mine - when only 1 lot at a time loads. That makes no sense and I cannot see that excuse as acceptable. Remove the fake and give us empty lots.