We just do carry on, 2 adults & 2 children, sun holidays.
BUT we have an apartment with a washing machine which I run every evening when we go out for a meal. Hang out when we get back and it's dry by the morning.
For the kids I take 2/3/4 pairs of shorts (less as they get older as they don't spill stuff all the time), 4 t shirts, few sets of undies, pjs, couple of swimmers. They wear sandals and I don't bother with other footwear.
They have 1 carry in between them which includes their beach towels.
For me I had 2 pairs of shorts, 3 sun dresses, 4 or 5 tshirts, few bikinis, couple of wraps, few pairs of pants.
I have 1 carry on with both mine and DP's beach towels, plus other random bits.
DP has to be persuaded not to take 2 jumpers and 3 pairs of long trousers (we are going to southern Spain in July you DO NOT need a jumper).
He more than fills his carry on then has to cut down on what he takes.
To be fair his clothes are buggers than mine, but he still takes too much.
I also take goggles, flippers, cards, books, gadgets galore (I think this year we had 14 including cameras which is ridiculous) plus chargers, beach bag, smaller cooler bag and a few other bits.
We take some toiletries
We also had a couple of v small dag packs, mine with passports, my purse, etc and kids with their bits and pieces for the flight.