How to manage 8 sim household?

wow that is a challenge. Not sure if I could do that. Don't even want to try, It would stress me out to much. But I am sure it is fun for others as it seem so.

I'm playing a 8 sim house at the moment, one adult and the rest are kids, I've played them since they were babies.
I have one large bathroom, separated into two toilets one shower and one bath, two sinks are in the main bathroom entrance.
I try to keep everyone in the green, mum now has level 9 maintenance 10 cooking, 8 painting and 7 gardening, she doesn't have time to work, too busy fixing upgrading, cooking. she also has a club that come to the house and garden, paint and fix stuff. she can sell the painting other sims do and keeps the money. she now has a gardener to.

I agree with what everyone has said, pause is your friend, especially when needing to empty their inventories and line up what you want them to do. sims 4 is easier for lining things up because we can click on their needs panel, but you need to check that because sometimes they don't do it or change it.
have plenty of things for them to do, like monkey bars science tables ect. family time is when their eating and watching tv at the same time, they eat talk and watch, so all three needs are going up together. and when they have friends come over, I put the friends in a small group with one child from the family, then they can grab a plate together and do homework together. I don't play with a large group because then I have glitches and everyone freezes. mum usually has to make two group meals when friends come over.

Also use the largest meal option and save unused meals using the "put away" option. This gives everybody something to eat when they go to the fridge when the chief cook is not around. Clear food gone bad away regularly.
Order food and put it in the fridge.

Apples are good to put in every Sims inventory. They can stop them from starving so get harvesting.

Actually, I have to confess, if I don't have a full boat, so to speak, I get bored.

I dont have problem in magane 8 sims. They are automatic eat，have fun and sleep. But you need to put beds ， lock door and put enough privancy washroom setting for such a big hold.

Also i will have one sims just do cook a couple of big dishes ready when they want to eat. Also with the maid someone help to clean house a bit. I think its ok.

I just got GT and made a cleaning and repair club, so club members come over to clean the house and fix broken stuff. It helps so much, no more hiring maids that don't work or letting household messes pile up. :)

8 sims is a challenge :o I find that storing leftovers is a lifesaver. Also instead of buying entertainment like a TV, getting a skill item like an instrument or chess set or easel so that your sims are forced to improve their skills to have fun :)

If i have a household that big i press pause ALOT

when i have lots of sims in 1 household and i need them to all take care of their needs without distractions i always pause the game, and click on each interaction i need them to do, then resume the game so they all go and do them ! i find its the easiest way to quickly get all sims needs up.

In addition to pausing occasionally, another good idea is time management. Make sure your you have enough facilities in your home to meet everyone's needs. I tend to go for a ratio of about 1 bathroom to every 2-3 sims. Have a primary care sim for maintenance and cooking that doesn't have a job. If you have kids they are gone for a decent chunk of the day and can get some of their needs handled while at school, same for working adults.

Have your primary care sim have a meal ready at least a couple hours before your family will need to hit the hay for the evening, as your sims are eating pause and take a look at all needs, I tend to prioritize the bladder and hygiene needs of kids (my adults have really good beds) so they get first dibs on the bathrooms. Just cue up the the bathroom needs of whoever needs to sleep earliest.

But yeah, to wrap up, schedule your sims to do certain things at certain times of day. Once they're on a schedule everything goes smoother. If you have autonomy on sims will also do a fairly decent job of caring for themselves.