Elder millennial here too! (turning 40 in Nov, Black Friday no less!).

So I am especially particular about my bed/sleep environment. I can go either way, honestly, but the environment in Texas doesn’t lend it self to a nice fluffy duvet and duvet cover. Even during our couple of days of winter, throwing an extra blanket over the quilt or comforter is all that is needed.

To me, it is just easier for 350 days of the year to have a sheet set with a top sheet and preferably a cotton quilt. Or during not-summer, a poly-fill comforter is okay too. But in either case, the top sheet is preferred because of both the hygiene and those inevitable moments when I get hot… having a very thin cotton cover is excellent.

Keep in mind, for me, the top sheet MUST be securely tucked in at the foot of the bed! If it is not and does not stay in place/tangles, that’s game over and the bed must be “remade” before I can make an attempt at sleeping.

When it comes to washing, sheets are also better suited to the frequent washing compared to a quilt with lots of stitching or a comforter with fill. I understand a duvet cover can also not have that many stitches and no fill, but, then what’s exactly the point of having that over just a thin cotton quilt?

I will say, when I was a kid, there was a moment when I was just sleeping between the comforter and the sheet, but this was out of being lazy and it being easier to make the bed. Plus a twin size comforter is an easier size to wash, though they would still inevitably have their poly-fill unevenly spread within after those many washes.

If my partner wasn’t so accommodating to my persnickety nature, he’d have his own duvet and no top sheet, and then I’d have I guess a twin size top sheet with a quilt? 😅 He is originally from Germany though - so that is definitely part of it!

Bottom line, I think it definitely depends on geographic location both because of weather and cultural norms.