We didn't want to use one so we never bought one in the first place and never thought of using one when we had any problems so we never missed them. If bub was sucky I found a sling invaluable because they could stay on me all day if they wanted to. Sometimes my nipples had had enough so dh would let them suck on his finger. None of my three are thumb suckers or have any other kind of comforter that they are attached to. I was told that I was letting them use my breast as a dummy but that never made sense to me since a dummy is a breast substitute. I heard of a good rule of thumb for dummies or any other kind of baby accessories - ask yourself if you are using it to meet your baby's needs or to avoid meeting your baby's needs and if the former then you can't go wrong.