I'm lazy and with just 1 bp I get the bag. I don't have to wait for it to expand. If I had more than 1 bp then I would get the bricks. I've never had a problem with dusty coco husk. I also mist it with a hand spray bottle though. If its old then yes you will have a problem with dust because it will be dry. I've never had a problem with mold either because I don't let it get too wet. Good luck on what ever you choose.