I've read in the past that you should not leave your sleeping bag stuffed in its compression sack. It supposedly damages the insulation. Is there any truth to this?

I've already got a few bags hanging in a closet taking up a lot of room and I need to buy more bags for the kids. The bags were packed in their stuff sack from the factory and they sat on a retailers shelf for a period of time so I couldn't imagine the damage being too severe

Unless you were going to camp in sub zero temperatures, I would not worry about it.

Definitely truth to it with a down bag. I don't think synthetics are affected nearly to the same extent.

First it was barrel break in procedures. Now there's a proper way to store a sleeping bag....who knew??

We hang ours, both down and synthetic. We have the room, so why not?

Yes it will clump the down. Then u get cold spots in the bag

With Synthetic its not an issue

And barrel break in procedure is a thing. It makes a difference

The last 3 bags we bought (North Face) come with a compression sack and mesh bag for storage. We toss them on top of a shelf in the game closet and they stay fresh. I toss our poncho liners in with them.

Down or synthetic, storing it compressed will rapidly decrease the loft of the insulation.

Don't compress. Makes a difference long term. Is there room under a bed to lay them out? Mine hang in a closet but you can use under bed storage or top shelf of a closet.

https://www.rei.com/learn/expert-advice/how-to-store-a-sleeping-bag.html

one of many articles on why not to compress either type bag.

I store mine in storage sacks such as the below. I throw the compression bag into the bag to keep it all together. Cheap insurance to make sure you stay warm when you really need it.

https://www.rei.com/product/112305/rei-co-op-sleeping-bag-storage-sack