I play multigenerational households so I get to families of 8 sometimes. It's not as fun, and I have to pause it so often that it takes forever to get through a sim week. Inevitably I will not make my goals with some of the sims in the house before they age up due to divided attention. It gives my save more variety to have some large households and some tiny ones, so I don't avoid it totally I just don't let most families have more than one pregnancy so they max out at 2 kids (maybe I'll see triplets someday but not so far).
Currently a lot of my households have 4-6 sims (1-2 grandparents Adult or Elders, 2 parents YA or Adult, 1-2 kids infant-teen). The ones with fewer than that mostly are small because the heir hasn't fully grown up or married or had kids yet and the grandparents either live elsewhere or have died. The way I've been doing aging (with MCCC and potions of youth for elders) the grandparents tend to die of old age while their grandchildren are teens so I've never had 4 generations in the same household.