How often do you create families and households that have multiple sims?

Very rarely. With my current family I created a female and male sim in separate households. Played the female sim for a bit then had them meet and marry after a while. They've had three daughters. Triplets who have aged up at different times.

I subsequently created the mom and dad's parents, siblings and their children, to provide relatives for my sim family.

It's been a few years since I created the extended family so the last time I was in CAS to make a new sim was for a few if the scenarios.