There's a bit of construction going on at the place I'm living. While X part of the house is disatached, the homeowner is having insulation put in. Older house, only insulated where there's access...which isn't much, unless there's some construction going on.
So she's decided to start installing Denim. It's a great noise canceler, it's healthier, and it's more expensive. She's already payed for it. i go out and what do I see laying beside the house? Cheep fiberglass. Which is not healthy, not as good a noise insulator, AND about 30% cheaper.
On the upside, I just earned myself a couple months of free rent for catching it!