It depends on the size of your bench cushion and where you're planning to put the bench, but usually, the friction of the fabric on the bench keeps it from moving around too much. If you're putting it in your kid's room like I did, I'd recommend permanently attaching it, just in case! If you leave it unattached, the fabric usually provides enough padding to keep the staples from rubbing. But if you're worried about the staples scratching the bench (or about the entire cushion slipping) grab a non-slip drawer liner, or a non-slip rug pad and put it under the cushion to help keep it in place.