We may not have multi-acre farms to take care of anymore, which is supposedly the reason that folks had large families in the old days. I find, though, that as a second-generation homeschooling family we need a lot of people in the house to make it through life. Let me explain what I mean through a bit of advice and experience.
If you are newly homeschooling (the on-your-own kind, not virtual public school) you will find yourself a little giddy the moment you realize that you have freedom-- freedom from schedules imposed on you by others. Sometimes it takes a while before it dawns on you that you can do your weekend stuff on a weekday, and avoid the crowds. This applies to shopping or vacationing.
After that comes the idea that you can go somewhere--anywhere-- because your school is on your own time and portable. This realization creates a huge desire to travel- educational travel. If you can't travel the globe, at least you could drive around to all the historical sights in the continental US. You need an RV or some kind of trailer to make that work, so you start renovating one or building one. Then you might get the idea to do a blog or a YouTube channel to document the crazy project. This is because after homeschooling a while, you start to get entrepreneurial.
That's right, you will start enterprises that stretch you thin, attempt huge projects that require manpower, and get ideas in the middle of the night of family businesses and creative ideas that are totally "out of the box" and make you so excited you can't sleep. This is often why homeschoolers are night owls. And this is why you need more people.
You have to have someone to learn to repair and operate
those strange things you pick up from auctions-- printing presses or
industrial leather sewing machines or other gadgets that strike your fancy for starting a home business. You have to have a teen who can program computers, do graphic design, and troubleshoot internet problems so you can have a website. You have to have a social media secretary, a photographer, content editor, and illustrator for all those books you write. You have to have a cook, car mechanic, plumber, electrician, and divvy chores amongst them all so your laundry doesn't edge you out of the house. You have to have several drivers to deliver goods or go to the post office. You have to have someone who can spin and weave and sew clothes. You have to have these things in-house because as homeschoolers, you start to get a frugal DO IT YOURSELF mentality and how great it would be for the kids to know these skills.
I warn you: it's just a matter of time before you, the new homeschool family, become a homesteading family as well. You will not only be schooling at home, you will be cooking at home (from scratch), growing your own garden, and pretty soon here come the chickens (or goats). You will need more land and start looking around for a small farm, because your kids really need to live an amazing life in the country. Off-grid.
Then you might start thinking that you need to build a house, or a tiny house, or a series of tiny houses (one for each person), because that would be such a cool experience for the kids (free labor). At least you will need a barn because horses or cows might show up next. Here comes the tractor, Dad needs extra hands with the haying, and mom needs help with the cooking. You are still holding down a regular job, but at least you know that the kids are putting up the solar panels while you are at work.
As you may have gathered, half a dozen children are not enough for such feats.
As the kids grow up and leave home, the homeschooling parent does not cease to need all this help. Your kids may have grown and left the nest, but you are still full of ideas, still running a home business, now more dedicated to eating organically from your own sustainable farm, and still collecting educational books (a habit). You still have homeschooling energy and have to do something with it. Technology has probably gotten weirder for your to figure out, and you still need ten year olds around to help you find the phone button on your new phone.
So you see, the second generation is needed to help the non-retiring homeschool grandma and grandpa, as well as being essential to their own family's home business/farm/chores. This is why it is good to have children spaced out for at least a decade (better two), so that while you are waiting for grandchildren to grow up and come back and help your family business you still have some at home. Make sure that you encourage your married children to have at least ten kids each, because not all of them will live close by.