We've noticed over the years that there are some consistent patterns related to family behavior that are tied to family size.
For example, parents of 3 kids suddenly seem to develop this unflappableness--they respond calmly to just about everything in a way that parents of one or two often don't (not always--I know some very unflappable parents of two). I don't know why that is--maybe because you've seen it all already? Maybe because you're too tired to care anymore? They also hover a little less than many parents of one or two. You can't keep your eyes on 3 people all the time, so you have to learn to trust them. And to run when the house gets quiet.
Other parents say three is when you can't hold everyone's hand anymore when you're crossing the parking lot, and it's true. And it's true outside of the parking lot, too. You just can't hold that many hands in any realm, so the kids have to learn to not need it, and so do the parents.
One thing I've noticed consistently is that parents who haven't crossed the thresholds can't comprehend them. For example, parents of three kids really don't believe me when I say "Four is different. It's a threshold where everything changes, just like having one kids was a threshold where everything changed." They insist that nothing will be different between three and four kids--they're already experienced mommies, and they have their systems in place to deal with the chaos of having a lot of little needy bodies running around. Usually, I just shrug and say, "If you ever have four, you'll see what I'm talking about."
4 kids is one of the major thresholds, and the one people least comprehend until they experience it. In fact, when I try to explain it to parents with fewer than 4 kids, they insist I'm wrong. But when I try to explain it to parents of 4 or more, they just nod. Four is when you stop doing playdates, stop volunteering for stuff, stop offering to bring, well, anything to anything. It's where you suddenly find you actually can't keep up with the housework quite as well as you'd like. You stop caring if anyone is wearing matching clothes, or even if they're fully dressed when you're at home. It's the place where you stop fighting with the kid who hates underwear or socks and tell them as long as they're modest and safe, you don't care what's on underneath (or not on, as the case may be). Life is more home-focused, and you just don't go out as often. And when you do go out, you try to do it when someone else can watch at least some of the kids--shopping after daddy's home from work, for example, or doing library trips in shifts (big kids and little kids at different times with different parents). Four is where most adult projects go by the wayside, and you start saying, "Some day I'll paint that room" instead of just doing it. My mom said four kids it the spot she stopped making her own clothes. Parents of four are more likely to do crazy things like let their kids ride bikes in the house--and look at you blankly when you protest because, well, what's wrong with riding bikes in the house?
With 7 kids, I feel like we've crossed another threshold, just like we did at 4. For one thing, I get horrified stares when I answer the question, "How many kids do you have?" I used to get admiring looks, now people are aghast and quite literally dumbfounded. It's not like I said I have 20 children, but you'd think I did by their reactions. It's almost as if I should be ashamed of myself. Really strange. So we crossed the "acceptability" threshold. That might have happened when we had 6, and I just didn't care because we are so nonconformist anyway because of the sleep disorder. But seven is definitely something a lot of people haven't heard in years--even if they grew up in a big family. With 7, we now have twice the number of kids people in our generation mean when they say, "I always wanted a big family." So we're a circus sideshow.
We're also in a world where buying things has become a problem. People don't sell 7+ packs of things (even party favors come in packs of 4 or 6). It's hard to find a vehicle that holds more than 8 people--even 8 was hard to find, but more than that and you're in the world of daycares and churches. Frequently, even the cashiers ask, "What are you going to do with 30 lbs of strawberries?" Um...eat them? or "30 lbs of strawberries? You must be putting on an event. Is it a party?" "Well, I guess you could call it that. I call it snack time." We also get a lot of, "Gosh, six gallons of milk?" I usually say, "It's all the fridge will fit," before I realize they mean "Whoa--a lot!" when I'm thinking, "Gosh, I wish I could fit more..." (Once I met a lady in the store (another customer) who said, "Six gallons of milk?" and I said, "I have six kids" (and I was very obviously pregnant with a seventh). She said, "I used to buy fifteen at a time. I had 8 kids." Instant bond! She "got" everything I was doing.). So we end up having to buy two boxes of everything and then trying to figure out what to do with the five extras....suddenly I find myself giving my big kids math challenges: "What multiple of 7 is also a multiple of 6? Is there one smaller than 42?" Or "What multiple of 7 is also a multiple of 3? Any less than 21? I don't really want to buy 21 donuts....What about multiples of 9--maybe me and Daddy can each have one." Of course, someone invariably says, 'But Mom, Jack is too little" before I remember that detail.
For another, I've moved into a world where efficiency is king. Anything that can be done must be done in the simplest way possible with least energy expended. (Cold cereal instead of scrambled eggs for breakfast, for example, because it takes fewer steps and requires less adult supervision). Anything that doesn't have to be done goes away or stays undone. We no longer fold the kids' clothes--they either do it themselves, or they get to deal with wrinkled clothes (we do sort them now, though, because that effort is actually easier than the consequences of not sorting them--and I know all too well, from experience). Baths are not a daily events for everyone in the family. Diapers mostly get changed when they are about to leak or are smelly. Dinner gets served in the pot it was cooked in (you mean I am supposed to transfer it to a nicer dish just for the looks of it? For real? And wash all those extra dishes?). Every recipe gets doubled, at minimum, but if a recipe requires more than about 5 steps, it gets thrown out completely.
It's just a different world when you're running a herd!