S.S.
I let my boys decide what they needed to sleep comfortably in from the age of 5.
We gave them sheets, blankets and pillows. They got to choose them. How they used them? it was on them. I have one son who needs to have 3 blankets over him (we are now considering getting him a weighted blanket) to feel warm and comfy. I have one that just wants a thicker sheet, like a hospital sheet. I have one that wears just underwear and a blanket and one that just likes to be "normal"!! LOL, what he has experienced at other people's houses: a sheet, blanket and pillow.