How do you decide when enough is enough?

I play long life rotational & had a bad habit of always maxing out the households (two parents, six kids). I was almost on my way to doing that with my newer save I'm playing now. Then today at work it occurred to me, each rotation is four sim weeks, or 1 "year" (4 seasons), so I decided they can have as many children as they like in the first "year" of their marriage/relationship, but then that's it. The first family I played had three children, my current household has two, with about a week & a half on their current rotation. Abduction children will be the exception. We'll see how it works out, I can't seem to say no when they roll a try for baby wish.