Having hand luggage only really makes you think about what you actually need to take for 1 week.
We take a jumper/cardigan each and wear it on the plane. Wear trainers, flip flops in the luggage. When you're in sunny resorts you just mostly wear swimmers anyway.
There's maybe 4 rucksacks to take on board... Kids clothes take next to no room. Swimming costume each, a few pairs of pants, 2 t-shirts and shorts / dresses. We don't bother with PJs on holiday. Waste of space!
Adults can take same sort, men take 2 shorts, 2 tops, 3 underwear, maybe one pair of spare socks, swimmers.
I wear shorts and t-shirt out, maybe take a floaty dress or 2.
Fuck taking makeup and 12 lotions, especially if staying in a hotel with toiletries provided.
Then it's charger leads, a book each, kids take books a small toy and a small cuddly.
There's plenty of room between the four bags for everything.
I find if we take a suitcase, we fill it!