At 31, I found myself with 5 kids living here, 2 bios and 3 SKs, all between 9 and 14.  Here are some coping measures in case anyone can use them.

Clothes:  The kids were close in age, all wore jeans so it was hard to keep it straight.  So, I made a code in cross-stitch inside the waistband.  One X meant they were the oldest's jeans.  Two Xs = second kid, etc.  So when someone outgrew their jeans and passed them down, I'd add an X.  That was the only way I could sort the laundry correctly.  Also, the 3 boys all wore tube socks.  Blue band = OSS, red band = DS, any other color = YSS.  Since I'm not a ball of fire, I usually piled all clean laundry in a chair in our room, "The pile".  But with the coding, they could find their own clothes.

Food:  I went to the grocery each week and loaded up one basket, I refused to do more baskets even if someone were with me (you have to have standards lol.)  They'd eat thru it and I'd go back.  I'd hear people whining about high food costs (in the 70s) but I couldn't even go there:  I had 7 people to feed.  I'd fix dinner and whoever ate, ate.  Some of the SKs were picky so they'd either fix themselves something else or DH might dole out fast food $, within walking distance.  I didnt have the time or energy to cater to special tastes.  They all lived thru it 

Back to school clothes:  I ordered as much online as I could, like underwear.  Back then, it was the catalog but same idea.  Nowadays, I'd do backpacks and school supplies.  I'd take each child, one at a time, to the jean store and shoe store.

Household:  Again, I'm not the most energetic person and didnt care if the place looked entirely perfect.  I shut the doors on their rooms and kept the common areas straightened.  Once in awhile, I'd hire cleaning help to shovel out their rooms.  

Yard:  Sometimes, I'd look out and see lots of dandelions and think, I ought to go out and weed all that.  But, I realized we were raising human beings, not lawns at that time and decided to regard them as yellow flowers.  In the fall, we had a ton of leaves.  I'd get outside with a rake in the afternoon and as the kids came home, each had to give me a half hour of raking (much grumbling).

Gifts:  I made sure we spent the same on each child.  And, at Christmas, I made sure each had the same number of gifts.  A pain, yes, but their beady eyes were checking it all out.

Attitude:  we only have so much energy and emotion.  Raising kids, especially SKs, is exhausting.  I tried to save my precious energy for DH and important issues with the kids.  Nobody remembers or cares about how the house and yard were but the kids often say, "Remember when you xyz or remember when you said such and such".  We made plenty of mistakes but tried our best each day.  Good luck, all.