There is a good thread on here somewhere with good packing info… when in doubt though, dont pack it. Both of my kids have asked for less stuff in their rooms each year they go back. The less stuff, the less they have to keep organized.
As far as cleanliness, I disagree with @vwlizard 's “never got bad” statement. Both of my kids have had filthy rooms. Kiddo1 was practically fermenting apple cider in her mini fridge freshman year, and the amount of dust in Kiddo2’s room this year was unfathomable. (Side note…the dyson fan/ air purifier is well worth the investment. Just make sure to replace the filter 2x a year.) Should you send your kids with cleaning supplies / a vacuum so they can clean their rooms? No, that would be a waste, bcs they wont clean their rooms. Should you bring cleaning supplies with you when you move them in / out and visit, so YOU can clean the room? Yes. While dorms do have some of these supplies, they never seem to be around when parents are around. If you’re not in driving distance, do buy cleaning supplies (stick vacuum, clorox wipes, swiffers, etc) to leave in your child’s room, knowing that they will only be touched when you are there.
Sheets are unlikely to be cleaned more than a handful of times. My kids don’t even bother putting a top sheet on their bed, and kiddo1 sleeps on top of her comforter. Don’t invest in bedding. Buy something that is comfortable, will last a few years (about 2 years for my kids), and then you can toss. Do buy a mattress pad. The mattresses are typically covered in nylon/plastic (?), so its nice to have some padding in between that and the sheets.
Buying a desk chair has been worth it for my kids. The flat bungee chair from the container store has been a favorite.
Neither of my kids have ever used a clip on lamp, in fact, I dont even think they’re allowed at one of their schools…Kiddo1 has used her desk lamp, Kiddo2 had a desk lamp provided.
One thing that is a bit “extra” but has been well worth it for my kiddos is a dorm headboard and/or giant pillow. Kiddo1 has the former, kiddo2 has the latter. Both options make the bed look a lot cozier and offer a place for the kids to sit up against, instead of being up against the wall. For kiddo2, it was especially important bcs there was a gap between his bed and the wall, so without that giant pillow, his regular pillows would have constantly been falling down.
As others have said, go with the minimum, and you can always pick up or amazon things you need once you see the room. Dorm rooms are typically tiny…and then when you’re splitting that space with someone else, there really isn’t a lot of room for extras.