I used them for about a week. I swaddled Kate and when I wanted to stop swaddling her I put her in a sleep sack for a week then just stopped using it. The sleep sacks would be great for a fall baby, I would think because the sleep sack acts like a blanket more than anything else. I know Kate needed to be swaddled tight or else her reflexes would cause her to "jerk" and wake up.
Heather, here is a link to their website.
https://www.halosleep.com/